The bitcoin developers are not sociopathic. They added merged mining to bitcoin fergoshsakes, so that altcoins can benefit from the security that bitcoin's massive hashing power can provide.
So far only Namecoin, Devcoin, Groupcoin, I0Coin, IXCoin, CoiLedCoin and GeistGeld have working implementations to actually take advantage of that extremely generous capability provided by the bitcoin developers but that seems mostly to do with scammers preferring not to make secure blockchains.
-MarkM-
This is all the same logic blackhat hackers use to justify their behaviors
"Well if you're security wasn't so poor, we wouldn't have stolen from you"
I guess if I leave my car unlocked I deserve to have things stolen from me. Gotcha.
Sadly, yes.
I mean, if some hackers can do it, what can big guys cause?
Everything that is possible WILL be done. That's why blackhat hackers do a serious job. If its not some stereotype blackhat hacker, then there will be state agencies doing it. If it is possible to fuck up bitcoin for instance, NSA for instance much likely has the power to do so. So, better some blackhats fuck you up and force you to fix your weak spots than some gov does it when it really thinks it has to.