Johnson’s already done it at least once. In 2025 he refused to seat Democrat Adjita Grijalva of Arizona who had won a special election. He kept making excuses as to why but the real reason appeared to be the budget battle shaping up in the House and he did not want to give the Dems another seat. She wasn’t seated for several weeks and after a lawsuit was filed. But at least one conservative scholar thought that he was legally within his rights to do this.
So there is a precedent, at least for single representatives. But since Trump doesn’t care about precedent, and he is already preparing the groundwork to declare fraud for any election the Pubs don’t win, and Johnson is a toady of Trump, I think it is well within the bounds of possibility that they’ll try something like this.
Would it dissolve the House and effectively shut down the government? Yes. Should one man (the Speaker) have that power? Hell no. But they are doing something analogous now - Johnson sent the House home several weeks ago to avoid a vote on impeaching Hegseth. If he refused to seat new representatives or convene the House, would the members try to revolt in some way and meet anyway? I’ve no idea. That’s uncharted territory as far as I am aware.
Anyway, I think that is a somewhat different scenario than the poll entry suggests, but YMMV. I also think “but that’s not legal” is not a reason to think they wouldn’t try it.