I'll tell you why, TS is notorious for trying anything to belittle St-Pierres in every way possible.
if he was to list those wins you've mentioned as well, he should've listed another two wins of McGregor as well (to keep the number of their best wins even) but since McGregor literally has no other big names on his resume, while GSP easily has 10+ quality wins.
It's not just that though, he fails to mention the context of the wins of both St-Pierre and McGregor for the same reason.
McGregor's best wins are almost exclusively against guys that are either significantly smaller than him or that were very unexperienced at the time. On the other side, GSP has cleaned out the whole welterweight-division - without having to cut so much weight that he's looked like a Zombie at the weigh ins, like Conor did.
McGregor isn't even in the conversation to be one of best fighters of all time, whereas if you combine the record of the opponents GSP, Jones, Aldo and Silva have won against inside the UFC, St-Pierre's opponents have the best win/loss-ratio out of those mentioned and with the exception of Bisping, all these wins happened at one of, if not the most stacked divisions ever as well, not to mention that Jones and Silva have tested positive for stuff.