They pay money to be advertised on those tags and they get it.

It may be annoying, and [there are Greasemonkey scripts to deal with it][1], but think of it this way:

What would you pay to use Server Fault (Or Stack Overflow)?

If that number is not zero, then consider this the price you pay for not having to pay that money.


  [1]: http://meta.stackexchange.com/questions/24065/user-script-to-remove-so-sponsored-tag-advertisements