This type of behavior is part of how men stand in jamaat in Arabic cultures. This is not how we were taught in Pakistan and India (Hanafi tareeqa). We stand with feet apart within shoulder length. We do stand shoulder to shoulder to allow for no gaps for “shaitaan to come through”.
I stand with my feet apart within my shoulder length but the guys next to me spread their feet apart further for their small toe to touch my small toe.
This unavoidable unless you go to a “Pakistani” mosque but if the behavior is adopted there from the Arabs then … it is what it is.