I am not an expert about TOR (or actually anything related to networks, websites or computers generally), but personally I think it is weird that one would want to sign in to TMO using TOR. Or sign in to anywhere via TOR. OR even use any clearnet websites via TOR at all.

I mean, to maintain anonymity, one should not link him/herself to any profile. If you sign in to Facebook using TOR, TOR prevents others to locate you by your IP. It prevents malicious people/apps to get access your computer, but does it matter when you compromise your anonymity by using public profile?

Another thing is, that the very limited capacity of TOR network should be spared for those who really need it. Nowadays every neurotic anonymity torchbearer use TOR network to watch youtube videos, read news and browse FB, which:
1. doesn't keep you anonyme if you sign in
2. takes quite a lot of bandwith


I'm aware that I oversimplify things a lot. And actually don't completely understand about what I'm talking about. But the point is, like I said above, why to use TOR and then personalize oneself by signing in.