"With great power comes great responsibility." That applies to the moderators, but it also applies to you. As the user with the highest rep on the site, that makes your posts somewhat of an implied standard.
People look at your posts and expect to say, "I see why this guy is at the top." And in that position, new users should not be using one of your posts as an excuse that their low-quality post was just like what the highest-rated user posted. Unfortunately, when you're a rock star, you live under a microscope, and you have more influence than a typical "private" citizen.
The fact is, that many of your answer are exemplary and the vast majority of them are at least good, solid answers. Occasionally, though, like this answer, you just phone it in.
Bounty questions aren't inherently special, but readers have an expectation that if people are competing for a bounty, they will put in a little extra effort to earn it. Bounty threads are in a spotlight and get a lot more scrutiny, and answers tend to be held to a higher standard.
So when the highest-rated user posts comment-fodder on a bounty question, it isn't surprising that the answer would get noticed and treated with more definitive attention than a random post by a random user.
Was the action excessive? Not every post of that quality by any user will be noticed, and if it is, it wouldn't necessarily be deleted. But being in the spotlight of a bounty, the treatment is also in the spotlight. Deletion was within the bounds of prescribed action, and you'reyour posts shouldn't appear to be subject to special, kid-glove treatment.
I'm not saying that it was, or might have been, treated more harshly. Rather the opposite. Site quality standards should apply based on the post, not the author. A bounty post is highly visible. To ignore a quality issue on such a post would have the appearance of special treatment for high-rep users. So it was appropriate and fair for a moderator to take some form of action on the post.
Was the action overboard ("reverse discrimination")? That's largely in the eye of the beholder. But when you're in a position of increased attention and scrutiny, avoid putting the moderator in a position where that question is raised.
All that said, the answer is now a good one and warrants undeletion. As far as the bounty, I'm not clear on the timing in this case, or the potential for a bounty to be retroactively fixed. Frankly, it would bother me to have a bounty awarded for the original post on a technicality if that's what was there at the time.
If the answer was improved to its current form during the bounty period but not undeleted in time for the bounty, responsibility for that seems to rest largely with you for posting the original version, the timeliness of improvement, and failure to flag the revision for undeletion as stipulated. That's all part of the learning process, and mistakes you won't make next time. Life is unfair.