I find the entire Uchiha Clan Massacre a bit odd for a couple reasons(aside from the whole genocide thing). Because Madara and Izuna were the first to awaken the mangekyou due to the requirements of feeling the pain of loss, then it stands to reason that more people within the clan should have it too because of the era they were living in where people were getting killed left and right, family members within the clan should feel anger over the loss of a parent or sibling or something like that. Soo the fact that itachi was the only one in generations to reawaken the mangekyou is ridiculous and also while madara was clan leader there were numerous uchiha following him all with sharingan of their own and the story is trying to tell me that none of them awakened the mangekyou?!!
Bullshit
There’s a misconception about the uchiha and the sharingan. Sharingans, even the base level 3-tomoe ones are supposed to be uncommon and “only elite uchiha” have them, according to Sasuke in part 1. Sharingans are not like the byakugans. All hyuuga have byakugans, but not every uchiha can awaken their sharingans, most never awaken them even tho everyone experience loss and grief at certain point in their life. I think that’s because only a small minority of uchiha have the genes for sharingan evolution. The large majority don’t carry the genes that make their eyeballs react to a surge of stress and develop new ocular power. If you consider even the base level sharingans are supposed to be rare, then it makes sense that there’re only 1 or 2 mangekyou users every generation as in the case that only Itachi and Shisui had mangekyou.
It makes Tobirama’s bigotry even more ridiculous, cos he’s just paranoid about a condition that only affects a small minority of Uchiha.