Plenty of ISPs spoof ping and other times it's a computer issue. It is very rarely ever something the user does themselves. Most cheaters don't even use ping spoofing, so thats just inaccurate.
And as for it giving people advantages, it has to be well beyond 200 to cause lag spikes drastic enough to cause issues in gameplay. Also if it gives such a massive advantage, then why are these people allowed to play just because they paid the bZ monthly subscription service (VIP). That's not logical. Either you are cultivating a good environment for as many people as possible (in which case VIP shouldn't grant ping protection), or you are implementing arbitrary rules in an effort to make people pay to be whitelisted so they are allowed the privilege of playing on the servers. I'm fine if that what bZ wants to do, I pay for VIP anyways, but booting people with no ping when it rarely causes issues, and giving them no solution beyond "pay us" seems a tad ridiculous. At that point it's not a donation, and it's not an effort to benefit the servers with good rules, it's simply a surcharge to play for some people.