Because he has his head so far up Marc's ass, they can't tell where he ends and Marc begins. He loves Marc (didn't we see him cry when Marc left? Didn't we? He cried so much...), and Marc loves anyone who he thinks loves him, so the parts of conversations in the bunker that we didn't see will have no doubt gone along the lines of:
Marc: 'Simon's great, because he cried when I left, but I'm gonna finger blast the rest of 'em, apart from Jade, cause she fancied me when she was 18, and Joel, cause he's really funny..(i.e. he's kissed my ass daily since he first set eyes on me)'
Helen: 'Marc says Joel is really funny, but I don't see it myself. Maybe when I get in there and meet him I'll see it (i.e. he's Marc's friend so I'll have to pretend he's funny when I meet him)'
Marc: 'Jack was a bit too pleased that I'd gone, let's finger blast him!'
Helen: 'Yeah, the fat c**t'