Right, but we can't read his mind. So in the end we are left with the exact same end result regardless his motivations. The problem with claiming you understand why he's lying, is that by your own admission, he is lying. And so you're assuming you can tell what is and is not a lie. And your best claim I've seen so far is we didn't see his views twist to what they are now in a slower pattern as if he was changing his mind about things. Now, that's not a far fetched claim except, there are VERY large chunks of time that we (thank god) are not around him. And by your own theory, he's just lying for his own end goals (attention/trying to hold up some centrist thing). So for all you know, he has changed gradually and you just never saw it because just like he's lying now, he could also have been lying in the past and saying things he didn't believe back then for the sake of his own end goals (maintaining income/popularity/ viewers)
No matter how you slice this, the argument that he doesnt believe anything he says and is just doing it for the lulz is self defeating without some kind of better evidence to back it up than what is basically your hunch. Especially when there are other things going on, like him admitting to abusing drugs, that are way more likely to have lead to him saying and believing stupid shit.