It has puzzled me too. I think it’s a combination of:

• above average raw charisma (people subconsciously want to relate to him)
• VERY generous / manufactured audiences
• our strong subconscious tendency to want to laugh along with others
• deliberate abuse of the “this is so funny I can’t help but break character” move, the most egregious and hateable thing the man does

People look at me like I slapped their mother when I say I find him 0% funny or likeable.