Asked a guy playing a stack deck what his wincon was; "ohh, my wincon is that you guys cant play the game anymore, I'll tell you when that happens"

The games before this stack deck came out was somewhat pleasant, but this guy was playing decks he was making sure to let us know he didnt think was any good (eldrazi deck that still performed good enough to make him the main threat at times). When he started to bring out the decks he like it just killed the mood at the table. Stacks deck with things that just shut us down more and more.

Is it me being a bad sport or is playing in such a manner somewhat shitty? Genuin question from newish player.