One presumes It's because...
They enjoy it.
People do all kinds of wacky things because they find them to be pleasurable. That's not hard to understand, in my opinion.
[FW] Spider AL
Hewwo, meesa Jar-Jar Binks. Yeah. Excusing me, but me needs to go bust meesa head in with dissa claw-hammer, because yousa have stripped away meesa will to living.