That is a horrible design decision. Why not let the user decide if they want to keep a history or not? Better yet, give the user the ability to flag apps as favorites or put apps on a 'wish list'. It is a far better design strategy to give the user choices
and control over how they wish to manage their data. (I.e., app history)
I can't speak for everybody but, for myself, the reason those apps are uninstalled is because I tried them and didn't like them. The design feature you speak of seems more like a "feature cut" decision was made and thus we are left with an inflexible product
that is, by the way, grossly inferior to its competitors. Worse than having a second-rate app store is one that, due to this design decision, discourages people from "experimenting" and trying out apps. The consequence of "trying" an app is that you will
have to deal with its existence cluttering up the "My Apps" part of the store.
In summary, give the end-user choice and control over their data. Microsoft is too far behind the curve in this game to make rookie mistakes that their competitors have already overcome. You need to be solid and, at least, on-par with your competition
before you can hope that your "differentiating features" will be noticed and embraced.
Please, if you have any power to do so, submit a DCR to the engineering team to change this aspect of the service.