MAN CAVE NO.1 looks to be yet another "fan" that Clem is turning his nose up to. Clem expects and takes praise for granted whilst anything else that doesn't fit into that mindset causes him to rage.
Personally, I'm not so keen on this MAN CAVE No.1 fellow, and this recent comment on the spambots video really crystallized my reservations. Here, we see that MAN CAVE No.1 objects to inbox spam, because it is distracting Clem from HIS messages:
Speaking quite generally, if one has difficulty navigating the world due to physical limitations or lack of social awareness, one starts attracting people who like feeling they are easily accepted and needed. Often, these are people who don't have much to offer anyone who is in a position to choose their friends. These people like you better when you are sicker or needier, because this increases their relative importance in your life.
MAN CAVE No.1 probably sees himself as doing a good deed by reaching out to someone who appears isolated and often visibly depressed. But I don't think he's actually being a good friend to Clement.
When Clem posted the video with his really disgusting bed, MAN CAVE No.1 told him to ignore the haters and reassured him that this was an acceptable way to maintain and depict one's personal environment. This was almost certainly intended to make Clem feel better, but it was still bad advice. Appearing to be a dirty stinky person puts one at an immediate social disadvantage, and a good friend doesn't encourage this lack of awareness in someone they care about.
Similarly, when Clem revealed his personal information to the world at large, MAN CAVE No.1 publicly insisted he didn't care, and in the video about the spambots, one can see he privately apologized to Clem for putting him in that position in the first place. But Clem knows he shouldn't reveal this kind of information in his videos, and he is capable of taking steps to avoid it - treating him like an infant or moron incapable of learning is not what a good friend should do.
It's unpleasant to see someone who claims to be a friend and fan give more harmful advice than many ostensible trolls. If Clem is, in fact, ignoring this guy, I would not feel too bad about it.