[corobo]

That is a fair point, in my experience Tor is just used by bots to spam comments up with junk.

This is probably different for larger sites of course but on our scale there's no worries blocking Tor

Edit: Although thinking about it I don't know any ads that aren't served up without some form of Javascript

[Houshalter]

The problem is that every website does the same thing, and now it's impossible to use the internet anonymously. But actual spammers can spend a few bucks on IP rotating services. IP discrimination causes far more harm than good.

Actually I don't think Tor disables javascript by default anymore, but even when I do disable it I still see ads.

[Scoundreller]

If comments were blocked, that's one thing, but increasingly often access to the site as a whole gets blocked.