Why does everyone hate on Alien Covenant?

Prometheus was definitely a disappointment, so I've put off watching Covenant because everyone always says it's worse than Prometheus. I finally watched it tonight, and I thought it was a hell of a lot better. It's actually a good Alien movie imo.

Spoilers beware:

I enjoyed the synthetic, and I think they did a good job with both of them. I liked most of the crew, especially the lead actress. That relieved smile at the end was too cute. The actual aliens were bad ass too. The fight with the two "kids" was crazy. It's awesome to finally see aliens do crazy animal attacks. Especially loved the 360 tail attacks. The "it respected me" scene was cool too, that's such a great idea. They were relentless with their attacks and they just kept coming back.

I know people harp on what's Dr Shaw being killed between movies, but I think it works fine. Really shows you how evil David's become. I could have done without the obvious twist at the end, but whatever. Movies gotta movie, I guess.

I don't know what I'm missing. Do people dismiss the movie without seeing it or something?