I think your post here kinda highlights the secret to Tim's success and popularity in the house. He got away with saying and doing things that the other HMs couldn't because he usually did it in a way that came across as entertaining rather than malicious IMO. When you read what he said about Tully without the context just in print it certainly comes across as nasty, but, like you said, if you picture the way he would have said it all of a sudden it takes on a different effect. Also out of the house he can't use the diary room like he did in the house to justify what he did or sell the narrative he wanted to.
Would have I said that about Tully even if I thought it was true? probably not, but then again I'm not like Tim where I gained a heap of fans, won 250k and gotten a career out of giving my blunt and often amusing opinions the other HMs either. I remember there was an awesome thread here during the season about Tim's quotes. It was pretty much a favourite, and most of the quotes related around the other HMs in some way. I can understand why he wouldn't want to suddenly stop doing what gained him his popularity out of loyalty to Tully when let's be honest here, Tully was anything but loyal to Tim.
I also can't really buy into the idea that Tim has betrayed a friend by saying what he did about Tully. Tim's been pretty blunt both in and out of the house about who he considers his real friends and I've never seen Tully make that list.
Tim does a lot of stuff that makes me roll my eyes so much it physically hurts. It's not so much his actions but the way he acts when someone calls him out on them. Like changing his story when
@Tim called him out, or the way he carried on in the house when Boog called him out, or out of the house when Jade apparently got the cranks at him over his video. He says he owns stuff but he really doesn't. He'll either throw it back at the person calling him out on his fuck up or lie.
I do think the guy is a ticking time bomb because sooner or later he's going to burn the wrong bridges, but really I still can't find too much wrong with what he said about Tully when all things are considered.