To be fair Brown’s was a carbon copy of Morelos’ “get it up you” gesture against Motherwell, and Morelos got booked and Brown didn’t. So there’s your consistency. Brown gets away with murder up in Scotland.
It’s just that Brown while performing his own “get it up you” gesture was a bit more streetwise when doing his and didn’t go right up to the Rangers support.
So I’m not really understanding your consistency comment. Refs consistently send Morelos off, for incidents which other players wouldn’t get sent off for. If you look at all of his red cards in isolation, maybe only 1 or 2 of them could be argued as red cards.