I think its because the one who have the bigger tendency to dominate is also the alpha one, thats why they are also the one who take action to locked their partner instinctively first. Not to talk about the animalistic instinct (Man, I hate to bring this up but its surely couldnt ignore in this universe).
But the thing I love about the omegaverse in this If-You-Can series is that is the dominant omega who can knock the alpha out, the very dominant one on top of that, like what Dane did to Grayson multiple times before.
Havent seen that 'power' in other stories before. So the omega is not wholely 'weaker' here.
I mean, the dom omega practicaly could do more than just knock them up, Dane literally force and attack (rape) him too.
Oh its supposed to be weird lol but also interesting these stories its always the alpha doing the chasing and the uke running away and then going into heat lol
i dont know if im the only one who thinks this but the omega being the one who was supposed to be locked up feels so misogynistic to me, i know his parents are both males but the thought of the more manly one locking up the more feminine one is so WEIRD to me