Is bullying ever deserved - no.
However, within the confines of the Big Brother house, the housemates can choose who they do or don't want to spend time with, and - if they prefer not to sit at a table with Perez (or anybody else) - then that is their choice.
It's not compulsory to talk to him, spend time with him, attempt to socialise with him, and I would say that their behaviour doesn't come out of thin air - it's a reaction to the last couple of weeks. Just as Perez choosing not to talk to a housemate or to ignore them (as he has done) is also his choice.
However, somebody rallying them regularly and saying to everybody, let's all consciously avoid, ignore, ostracise Perez, deliberately make him uncomfortable (rather than being polite and decent - if he talks to them in a polite, courteous way, they should respond in kind) and going out of their way to do so, I could never condone that.
I do believe there is a difference.
Best example I can think of, if I were at a party and there was somebody there I didn't want to talk to or see, I wouldn't go near them. I wouldn't, however, go around encouraging others to do the same or rallying others to start being nasty about that person or to that person. I just would avoid that person. Avoiding or ignoring somebody isn't bullying, it's a personal choice.
The other night during live feed, when most of the housemates were chatting about various things, having a nice time around the dinner table, Perez chose not to try and join them. Nobody said to him 'Perez, don't even think of joining us', he chose not to join or attempt to join them.
Had he tried to join them, being polite and friendly about it and then they had all walked away, that would have been very uncomfortable but then that would be their choice.
Had he tried to join them and somebody had said, come on everybody let's leave Perez here alone, he doesn't deserve our attention, then that would have been uncalled for.
I'm not using the word bullying as I don't see any bullying, just a lot of very opinionated people who (most of them anyway) have behaved pretty immaturely for most of the series.
Seems to me that peace has broken out though:
12.20am: Cami and Perez cook late night chicken and talk about childhood. Cheggers is told not to fuss about the washing up
Not two people I thought would even talk to each other!