Mcgregor bjj is fine, his gym is primarily grappling based, his head coach John Kavanagh is a black belt and that's his base, Conor has been competing in grappling since he was a teenager and Gunny Nelson is not too bad on the ground, you know.
McGregor is legit everywhere, he lost because he drained himself punching Nate skull.
Everyone that knows anything about fighting knows that, McGregor and his coaches admitted that, even Canelo Alvarez said that.
And if you know a thing or two about jits, you know that Mcgregor did a PERFECT x guard sweep on Diaz in the first round, something you rarely see in mma, and than he completely neutralized Diaz guard with perfect posture and landed bombs on top.
Conor problems were in the second round when he gassed, got rocked and turned into a panic wrestler.
We already seen legit black belts get submitted after they got rocked, like multiple times ADCC trial winner Vagner Rocha got submitted by Jake Matthews, after being hurt.
Stop with this "McGreagor is weak on the ground" bullshit, that's not true and you know that (if you don't know that stop posting and start taking bjj lessons, you keyboard warriors).
/end rant.