Clarification of the problem:
- Your misinterpretation of what a bounty is, and should be used for.
A bounty is designed to draw attention to a question, in the hopes of getting an answer so that if an answer solves it a user may get awarded the bounty. (Or, for those with excess reputation and can therefore afford it, to provide an incentive for others to answer a question, or to reward a good answer).
It is not designed for 'adoption' of a question, and you are not entitled the same permissions as you would have by posting the question yourself as a result. This ultimately means that to interact with a post you've put a bounty on, you would not open a bounty that would revoke the permissions you need for interaction with that post.
To quote Jeff Atwood's post on Meta.SE, on the question about splitting bounties from affecting permissions:
... bounties are for people who either
- feel like they have an excess of reputation and can "afford" it
- have an urgent need to get an answer and the normal process needs goosing
This does not fit your 'using bounties to adopt a question' view, and by design it cannot support that view.
- The unbreakable bond between Reputation and Permissions.
As stated in the Help Center, and elsewhere, including on Meta.SE, posting a bounty will affect your reputation level. It will also reduce your permissions based on the reputation level.
As was indicated by Jeff Atwood on Meta.SE, in regards to the Feature Request (on Meta.SE) to Exclude Bounties from Affecting Privileges, there's no really good way that can be thought of to separate bounties from the reputation system in a way that would allow for permissions to be retained when a bounty is posted; as such, it's unlikely to ever be implemented.
With this in mind, the feature request here is asking to permit commenting on awarded bounties, outside of the confines of the existing permissions system. This ultimately ties back to having to exclude bounty awards from reducing your permissions levels, because to comment on any post that is not your own you need to have 50 reputation. With no mechanism to separate the permissions, the feature can't be implemented without changing how permissions are affected by bounties. And Jeff has said this is unlikely to get implemented, which ultimately points back to the "Declined" status, and the "This is a problem with the existing system, and not one that is likely to be fixed/changed" nature of this answer.
