I've clashed with meat eaters in the past on this specific fact. The social media drip feed (and by that I mean, the anti-vegan pages) got us thinking we need to eat complete protein each and every single day just to be healthy. (besides meat being the only source of complete proteins)

Can you please provide some sources for this particular statement so that I have something to back up my argument when I duel with them the next time?

(or point me to which one of your linked sources contains this specific fact?)