I don't think it would be out of line at all. I got downvoted to hell for expressing similar opinions before but I think this is a perfectly reasonable opinion.

Facebook is in the business of social networking, not activism.

The number of users using Tor compared to the general population is bound to be so low that they either shouldn't care enough to bother blocking it or if they did for some reason, really wouldn't put a dent in their daily actives.

Activists very well could be screwed, but that's really not Facebook's concern. Their no pseudonym policy makes perfect sense. Whether or not you like it or would use services that enforce it is an entirely separate issue. I feel like I don't have to explain this but I will anyway. Using a real name helps them help you find people you know (or at least whose name you know). That's the whole point. To start implementing policies conducive to anonymity defeats the entire purpose of Facebook.

I understand why Facebook is such a great tool for activists and dissidents and why a social network built especially for those people would not be ideal. That said, at the end of the day Facebook has no obligation to support such people. The fact that it's such a great tool for activists is just a side effect of the app's main purpose and use by the general population. I'd even go so far as to say that if they blocked Tor purposely in the future no one would really have any right to be outraged. I mean, you can certainly and understandably be outraged, but you really can't say Facebook has wronged you as being a tool for activists isn't really their mission. Complaining that Facebook wants to collect info to show you ads is like complaining that the coffee shop requires that you give them money to be served. Tracking is the way you pay to use Facebook and I doubt they'd ever implement paid accounts to get rid of the tracking and ads.

I'm sure there are some who work at Facebook who feel a moral obligation to support those activities but at the end of the day its a business and it isn't a business founded upon principles that fall in line with those of activists. If Mozilla created a social network, maybe then we could say the company has a moral obligation to encourage anonymity where people wanted but that kind of philosophy is just not in Facebook's DNA.

if you must conduct sensitive work, why do it on Facebook, a network that is committed to sharing things in public?

Because of exactly that. It's public and the general population uses it for an entirely different reason. If you're doing sensitive work and need to get the message out then Facebook is a great tool for the job so long as you can remain anonymous. I know that's totally contradictory sounding but it's reasonably possible. Currently you can use Tor and other measures (assuming this issue is resolved) like using a fake name (which is technically a pseudonym but what I really mean is a name meant to look like a real person but isn't). Everyone uses it, you can let the world know important info, and though you can be rooted out, it makes it more difficult as you're a needle in a haystack. Compare this to a tool built specifically for activist communication - it's basically a big honeypot for unfriendly governments. They know that every user is a political dissident and now they really don't have to narrow down their search. They can just start hacking and tracking every user on the site.