I appreciate the concern, but the "why" was given in the first paragraph of the announcement thread. There is an influx of new members who are not as immediately familiar with topics as us old timers and if by changing a word or two to make a title more clear helps, we feel it is well worth it. Not only that, but by adding key words that are searched for or modifying a term to a more searched for term will also help when members use the site's search function to look for a topic of interest.
Implying this is somehow taking away a member's "choice of how to attract attention to their thread" is misleading at least and paranoid at worst.
If we were changing a title from "Guess what I got for Christmas" to "I got a new Luke Skywalker lightsaber for Christmas" it would be one thing, but to add simple information (usually a word or two) to better help members identify the content of a thread isn't taking away choice. It is unfortunate you choose to see it that way.