Heyya, its ok to complaint but at least give the reason why its bad from your perspective...
Just like:
"(you tasted a food) its suck! This food is trash! Idk why people is eating it"
I think it'll be better if:
"this is too salty, you need add some spice, i think it will be better if you change the meat with a shrimp and meatloaf from a shark"
Or something like that, it will tell us the food (in this context is the manga) is not suit to your taste but you also mention the reason why and what will make it better in your opinion, so the other readers (especially the new one) will know your thought (review?) about the food
And again, its fine to complaint but it will be better if you tell us the reason why 👍