Its all down to circumstance, example, when capping A on Steel, I see no problem having a heavy or something camping the spawn defenders spawn door, it has to be done to cap efficiently.
Now spawn camping when the attackers are on like the 5th point, just means that player camping is pretty lame and not helping his/her team out when they are struggling to defend.
Now you cant blame a spy for spawn camping, they are taking out teles and if you get killed by a spy when leaving spawn... good, you deserve it for being cocky and thinking your are safe.
On badly designed maps like dustbowl and goldrush, its really hard to avoid, as the defenders can physically sit on the spawn door. Or as what's commonly seen, the same pyro medic uber combo will sit at the door till they get whittled down. This really is hard to avoid, and hopefully the red team will not be twats and learn to retreat in order to not be viewed by everyone on the server, red and blu, as massive massive pricks with no skill.
Most spawns have two exits most of the time so as Blaze said, there reign of terror wont last long.
Personally, I normally just tell the person not to be lame and spawn camp, then go thoroughly rape the crap out of them till they learn their lesson.
Please excuse the term, tough love.
My issue is malicious, talentless spawn camping as can be done, for example only, by spies. Lurking around the corner from a spawn and nipping out to try and get some back-stabs before you get fried just reeks of point grinding. Killing people as they spawn (especially as most maps have multiple spawn points) does nothing to help your team as the people you are killing are not in the fight yet. All you are doing is bumping your score in a desperate attempt to look big and clever.
