@Ayubi,
I believe most of these resentments against polygamy are a reaction against some muslim men who take advantage of this by marrying a second wife and hiding it from their first wife. Ofcourse polygamy shouldn't be seen negatively if one has a need for it, the first wife agrees to it and he makes sure they are all treated fairly.
Al-Mawardi writes:
Al-Shafi’i recommended that a man limit himself to one wife, even though it is permissible for him to marry more, in order to protect himself from wronging them by inclining more to some of them or being unable to spend equally upon them.
Source: al-Ḥāwī al-Kabīr 11/417
Al-Fiqh Al-Manhaji 'ala Madhhab Al-Imam Ash-Shafi'i:
If there is no need for the polygamy, if its purpose is merely to add to [the husband's] enjoyment and comfort, and if there are doubts about his ability to establish justice between his wives, then the polygamy is disliked. This is because there is no need for it and because [the husband] may cause harm to his wives due to his inability to deal justly with them.
Best,
Faahiye