Why is calling people out hard?

A lot of feminist criticism* follows a certain pattern.  Person A says something horribly wrong.  Person B calls them out on it.  Person A either admits error or becomes really defensive and makes excuses.  All spectators begin to either berate person A or person B.  This whole process is painful, for both sides.

As a concrete example, see here.**  At an atheist conference, a speaker said it was nice to have a "pretty blonde Romanian" vlogger on our side.  Jen called him out for essentially reducing the vlogger to eye candy.  On the spot, the speaker made excuses, but by now he's offered a sincere apology.  This surely wasn't fun for the speaker, and it wasn't fun for Jen either.  Jen says:

Part of me hates blogging about stuff like this, because I don't want to promote in-fighting or tarnish an otherwise successful conference with this issue. But the more we let crap like this slide, the more it's going to get perpetuated.

Skeptics are also in the business of criticism, though a different kind of criticism.  So here's my question: why does skeptical criticism feel so much less painful?  Here are some possible ideas:

1. It's only a matter of perception.  Skeptical criticism is also really painful, but I'm more used to it.  Or maybe it's much more painful for the opponents of skepticism.  Or maybe I'm just lucky, and most skeptics do find skeptical criticism to be painful.
   
   
2. Feminist criticism is more likely to be targeted at friends and allies.  Like when a feminist skeptic criticizes fellow skeptics for scaring women away from the skeptical movement.  Or when friends or family make upsetting comments in front of you, and the only way to stop them is by confronting them.
   
   Skepticism is pretty painful too when you're confronting the weird beliefs of a relative.  But in my experience, this is usually avoidable.  Weird beliefs are harmful, but in many cases a relative's beliefs are no more harmful than a stranger's beliefs.  So why not stick to persuading strangers?  It's less painful and has the same effect.
   
   
3. Feminist criticism seems to have more of a moral dimension to it.  When someone calls you out, it feels like they are calling you sexist, even if no one actually says that.  Of course, the purpose isn't to make anyone feel bad, the intention is to stop people from saying wrong things.
   
   Contrast with skepticism.  If you do or say something worthy of skeptical criticism, it just feels like an innocent mistake.  At worst you feel stupid, which is unpleasant but easier to admit.
   
   
4. Feminists often fight a "fog" of discrimination.  It's not any one specific comment which is problematic, it's a whole series of comments and systematic biases which create an unfriendly climate.  This situation makes most people feel powerless.  How can you criticize a whole climate?
   
   Sometimes the easiest thing to do is to pull out the worst comment and make an example of it.  But no single example can capture the problem.  The critic feels afraid to make a big deal out of it.  The criticized feels unfairly attacked.  And everyone misses the forest for the trees.

Any other ideas?  Is there any way to alleviate these problems?

*I'm not thinking of just feminists.  A lot of other groups, like queers, ethnic minorities, and religious minorities, have the exact same issue.
**This is not the source of inspiration for this essay, just a convenient and recent example.