At least LoL had a lore, but it became to complicated to continue it and needed a revamp (which admitedly takes a tad too long)
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But what about other "Moba's" ?**
Smite:
The God's of the world's pantheon have come together to fight each other...
Because the humans stopped worshipping them, because they think they don't exist...
Yet most battles seem to be held on earth...
Were everyone could see that the gods exist...
Which makes the entire conflict moot.
Dota:
At least makes some sense (if you can call it that)
The Nexuses are two opposing "Gods" that brainwash the minions and heroes into fighting each other and the "Champions" have backstories that vary in quality (some better and some worse that the current lore [in my opinion]) mainly because a lot is kept open for interpretation.
Heroes of the Storm:
"Legends speak of a place where worlds collide and mighty heroes battle for dominance..."
There is a timy wimy space storm in which heroes from different universes come together and fight...
The different characters have lore from their main games, but they vary greatly in quality and require you to know the main game the character comes from.
Strife:
The "Heroes" fight in an arena because they train for a coming battle from an old prohecy...
Why they don't use the minions or the magical respawn ability in that battle is up to interpretation :P
The characters have different reasons to join this organisation. Some good and some badly written.
So yeah, "Moba's" and Lore seem to be hard to combine and the only reason why LoL gets called out for it, altough other games of the genre have similiar or worse Lore, is that LOL used to have a good Lore that sadly ended up having too many plotholes and getting retconned.
Only time will tell, how good the retconned Lore will be, but don't badmouth Riot because they have gone through the effort of making a Lore work in this setting, when no other game in the genre seems to be able to.
######All mentioned opinions are mine and mine only