If you have so many open sale threads that it bothers someone enough to post a rant, you probably ought to get an FFL before someone reports you to the ATF as well.
If they are from one's own collection and you aren't seemingly flipping guns the ATF will apologize for the inconvenience.
It's a fine line, but if you are honestly selling off guns you've had for years and not selling guns you bought last week over and over, I don't see the ATF giving a rip if it's 1 or 100 guns you are selling.