I've watched since the very first episode. Unless I've missed something, no-one has said that they are surprised by the nastiness. I'm happy to report though, that watching hasn't changed in any way my view on how people should be treated.

Nikki is a viewer and she's just been displaying her opinion on what she's seen from the outside as a viewer. I don't see any issue with that.

I would normally feel it was too cruel but at the same time Jack isn't a nice person - he has become insufferably arrogant and bossy as the series has gone on.

Sadly, this happens season after season. Also depending on which side of the argument you're looking at, often the nastiness goes unnoticed by the viewer.

I see an issue with her pretending to like Jack. Don't you? Talk about fake!

They really are making BB unwatchable.
How is nastiness, mental cruelty, picking on vulnerabilities, lying etc something to be applauded and anticipated with relish.
We are going back to the Dark Ages if that is what is regarded as good television.

i think it was said somewhere Jacks playing to what he think the crowd wants, well Nikki has just let herself down doing the same thing. it was cruel.
i love Nikki
but i also dont understand all the hate for Jack, he says what he thinks more than some of the others who want to sail through to the final.
Jack isnt the perfect male like people seem to think Marc is Jacks just human and has faults

Nikki is havin a bit of fun with him. She couldn't have made it more obvious to him that she was pulling his leg - if the buffoon falls for everything anyone says to him he has no business being on a reality game show.