I'd have no problem with you posting the same answer a million times over as long as they answered different questions. This is a case where it is not only clear that they are duplicate but also that you knew the older question existed because you posted to both within a matter of minutes.
If you were a new user, yeah, I'd probably suggest more delicate handling. We try to spend some time with new users explaining how the system works... But as you point out, you've got 65K of network reputation. You should have an idea that the massive duplicate system that exists on these sites isn't there just to be ignored.
And in terms of how we handle communication with users of deleted posts, the comments are sincerely not supposed to be a public lambasting. Some other people can see them but —save for when people open a meta question about it— very few people actually ever see the deleted post. We just want you to know why we're doing stuff so we don't get "Why did a moderator rudely delete my answer?!" meta-questions.
In short: The comment could have been more explanatory but you should probably know better too.
In terms of the duplicate process, when you mark something as duplicate, it leaves a comment for the OP. This is more than enough. You don't need to copy your (or every other answer) over. That's not desirable for anybody.
If the question is closed as duplicate, that comment is deleted and converted into the header you see above the question. That is what happened here:
