Yeah, yeah- that's great- my experience with that game online has been fine. It does matter if you use a wired over a wireless connection, what speeds you have, how things are in your general area and if you're using cable with a lot of users at peak times and all that stuff. I'm not making excuses for anyone, lol. It is still better to play via a wired connection from my experience.
You want to experience shit levels of connectivity in a PS4 fighting game? Go try DOA5 LR.
SC6 is fine. Tekken is fine too. Better on PC, but still fine on PS4. He had matches with two players with shitty connections and/or his connection was having issues, too. Maybe he got matched up with people in another region or country? Lots of variables here.