Bitcointalk is big forum filled with lots of smart guys, creators of the stratum protocol and i think if he point some transparent facts they will chime in, investigate, point some real facts and proof and than i will beleive. You know the saying "innocent untill proven guilty", sadly in this case he is "guilty until proven innocent".
Facts are plainly there for all to see, if you choose to open your eyes and see them for what they truly are. Problem is you do not want to see them for what they are.
1. There was a block with-holding attack which negatively affected pool luck
2. The said attack was detected, miner identified and,
after thorough investigation, the attack was attributed to buggy software
3. The offending miner's buggy software was patched with the un-doubtable expertise of the slushpool team which positively affected pool luck
The rest is the usual tripe by lesser pool operators fishing for miners, I have to say, slush keeps growing and that is telling.