Be sure to screen shot any comment you make that you want to preserve, or comments by others that should be preserved. LessWrong is now the sort of site where critical comments silently vanish that cannot by any sane stretch be called trolling.
If your concern is public relations, systematically deleting critique is amongst the stupidest things I can think of you doing. This is the Internet, where that sort of behaviour ensures preservation. A bot to automatically preserve all comments to LW would be ridiculously simple, for example, if MIRI could no longer be trusted to be honest.
Really, MIRI. Just what the hell do you think you're achieving with this?
If it's worth saying, but not worth its own post, even in Discussion, it goes here.