Why are the celestial frowned upon?

Basically because in a world of empires that use strength to rule over the rest and choose their leaders the celestials are pacifists
The empires and races are chosen by the game to match with the player so they basically are a fit to their personality.
So all the losers* and people that are less prone to fight back and are marginalised usually get the celestial, as such we can understand that the mentality of the kingdom is somewhat similar to the one of the player.
They are pacifists that dont like war and are usually supports as we can see form the other celestial kingdoms having mainly support skills (as well as mc)
Mc kingdom is an exception because he took a build that is basically a support and made a killing machine out of it
But the essence behind his power is still support skills (power of friendship

So lets put it in the prospective of real games : say that in LOL or any other similar game there is a character that has a shitty build/skills and most of the time when you fight against or with jt is super weak and useless, you wouldnt think differently about that character just because there is a singular high ranked gamer that knows how to use it to make it great, the game wouldnt need to patch it because nobody else can use that character that way and if you were to meet someone with that hero in a game you would expect them to be extremely weak.

Bcs they're perceived as "weak" by the others. That's why sehyun changed his kingdom's race into "dark celestial", bcs he don't want to see his vassals to die again and again.

I see a fellow orv fan and i weep again
The kids nowdays say 6/7 but i used to hear 49/51 and cry

Fellow orv fan!!! I wear that badge with pride... since we would never be able to escape from those numbers anyway...

Your @ gave me instant psychological damage the second i read it
Being a reader means being a masochist bc tell me why i love them even tho the story hurt me so much
( T﹏T )

It's been 6 years since I've read the novel and i still am NOT over it

You're not wrong, orv has turned us all into masochist bcs we refused to stay happy after all this time just like kim dokja＿|￣|○

power of love you mean, ahem