People who dismiss Zutara rudely do not do so because they don't have an argument, they dismiss it because it's laughable.
Would Zuko and Katara have made a better couple? Maybe, I have no idea. Was there, ever, even the slightest chance that they would be? No. Not even a smidgeon. AtLA is a kids cartoon show and Aang and Katara are the male and female lead, so they're going to end up together because that's how stuff like that is written. It's literally that simple. No one brings anything to the discussion because there IS no discussion. It's probable that most of the people who laugh at Zutarans don't ship Kataang, they just think Zutara is fucking ridiculous. Even the Kataan shippers presented their points NEARLY A DECADE AGO
Fucking seriously, people
Thefinale of Avatar: the Last Airbender aired in July of '08. Zutara is gone, sunk and dead, and it never floated very well to begin with *because Aang and Katara were the main characters and for literally no other reason*. Call it bad writing, call it hackneyed and mainstream, but don't try to pretend anything else was going to happen.