Steam – My loadout isn’t loading on most of the servers I go to

You could delete it and then make sure you clean out the Steam/steamapps/< yournick >/team fortress 2 folder.

However that would mean you'd have to redownload all of TF2, it's probably easier if you just redownload the Fancy vs. Nasty update, look inside it what files came with it and delete just those manually from above folder.
It's also probably a good idea to run "verify integrity of game cache" after that.

In the server menu is an option to search for VAC-secured servers There are NO official steam servers, There are only induvidual gamers and communities who run these.

Just looking for VAC secured servers should be enough to prevent having to deal with hackers. Othwerwise consider joining a community that has some good servers (I will not name any) Most bigger communities have admins on at most times and when you stick around them you might find some guys/gals who are great to hang around with.

Also consider that some people aren't actually hacking alltough I would allways accuse them of doing so, CS is one of these games where some people just developed insane skills