I strongly disagree both with the mod's decision to delete the post and with the way the post was handled.

In my opinion your suggestion of running the xz --version command is not problematic, since the OP is primarily concerned if an LTS is affected, which isn't. Running the command in an LTS is perfectly safe and reassuring for the OP to see that their version of xz is not the dangerous one.

The OP is also concerned if some other version is affected and, as you said, only 24.04 could be affected. Running the command in that version could pose a risk, however, 24.04 is still a development release, so if someone was running this release could already be at risk. Furthermore, if the OP was concerned specifically about 24.04, then their question would be off-topic and would get closed.

So for both the LTS and non-development releases, your answer is fine. It could be improved, however, by providing a way to check the installed version of xz without having to run it, so that the version checking would be safe for all releases. A safe version-checking command could be, for example:

apt-cache policy xz

So this would be a nice improvement to your post. So the user that flagged your post could have also commented below your answer and expressed their concerns instead of just flagging it, and that would have most likely led you to find another way of checking the package's version.

However, the flagger's action is not my main concern here. It's the mod's action that matters more. The mod could have also expressed their concerns and comment below your post to let you know what the issue is with your post and then proceed to deletion, which wasn't really required in my opinion, but would be acceptable. Instead, the mod chose to delete the post without any justification of his action. While deleting a post with an explanation for the reason deletion is not obligatory, it is a good practice that can also lead to post improvement and subsequent undeletion. Our goal after all in this site is to have as many good questions and answers as possible.

Just deleting the post without any explanation about the reason of deletion feels as an extreme authoritative action in this case. And mods shouldn't perform such actions lightly. Okay, I don't expect an explanation for the deletion of every flagged post that was handled by a mod, but in this case the post wasn't clearly bad (I still don't think it is and that it should be undeleted) and at least an explanation for the deletion reason should have been provided.

Additonally, there is another answer to the same question that suggests to run the same command. Is this answer less dangerous?

Finally, I would like to remind that mods are also users, just with more tools and bigger responsibilities than non-mods, that are supposed to set the example for the community. As the rest of the users, they should justify their actions and not abuse their authority.

I strongly disagree both with the mod's decision to delete the post and with the way the post was handled.

In my opinion your suggestion of running the xz --version command is not problematic, since the OP is primarily concerned if an LTS is affected, which isn't. Running the command in an LTS is perfectly safe and reassuring for the OP to see that their version of xz is not the dangerous one.

The OP is also concerned if some other version is affected and, as you said, only 24.04 could be affected. Running the command in that version could pose a risk, however, 24.04 is still a development release, so if someone was running this release could already be at risk. Furthermore, if the OP was concerned specifically about 24.04, then their question would be off-topic and would get closed.

So for both the LTS and non-development releases, your answer is fine. It could be improved, however, by providing a way to check the installed version of xz without having to run it, so that the version checking would be safe for all releases. A safe version-checking command could be, for example:

apt-cache policy xz-utils

So this would be a nice improvement to your post. So the user that flagged your post could have also commented below your answer and expressed their concerns instead of just flagging it, and that would have most likely led you to find another way of checking the package's version.

However, the flagger's action is not my main concern here. It's the mod's action that matters more. The mod could have also expressed their concerns and comment below your post to let you know what the issue is with your post and then proceed to deletion, which wasn't really required in my opinion, but would be acceptable. Instead, the mod chose to delete the post without any justification of his action. While deleting a post with an explanation for the reason deletion is not obligatory, it is a good practice that can also lead to post improvement and subsequent undeletion. Our goal after all in this site is to have as many good questions and answers as possible.

Just deleting the post without any explanation about the reason of deletion feels as an extreme authoritative action in this case. And mods shouldn't perform such actions lightly. Okay, I don't expect an explanation for the deletion of every flagged post that was handled by a mod, but in this case the post wasn't clearly bad (I still don't think it is and that it should be undeleted) and at least an explanation for the deletion reason should have been provided.

Additonally, there is another answer to the same question that suggests to run the same command. Is this answer less dangerous?

Finally, I would like to remind that mods are also users, just with more tools and bigger responsibilities than non-mods, that are supposed to set the example for the community. As the rest of the users, they should justify their actions and not abuse their authority.