It's not like 'Harem is a trash' but it only became like that because of how some authors execute the word 'harem'. Imagine, if the setting is modern with cultivation, there is a harem of women who flaunted at an OP male MC? I have read novels like that. At first, I thought it's okay at the start but when you read it longer, it became useless because the women are just like figurines at your display and they didn't even have the role for the MC. They just became a burden.
Kidnapping incident, saving the damsel in distress from forced marriage, irrational women if the MC helps them, etc.
I love reading different kinds of tropes and I don't care for the tags or whatsoever if the plot executes well.
I know everyone here has its opinions regarding the 'Harem' tag in every novel that you have read and I feel the same way.
I'm also writing a novel with a harem tag but in female leading. I am very careful of using my plot and I hope that I can execute this well in the future! _