when you're doing something in a group, that means you go at the pace of the slowest person so you all stay together unless there's a specific agreement that some people can go on ahead.
I remember going cycling with my dad and brother when I was about 8. I couldn't keep up, they made no effort to slow down for me even though I asked them to repeatedly. Finally I got fed up and went to cry in the 7/11 bathroom for like half an hour and they just cycled home without noticing. I got home almost an hour after them and they never even noticed or commented on it. Literally anything could have happened to me in the meantime.
I do think sometimes people get a competitive and sadistic streak when they are doing group fitness activities like this and it makes them look down on the "weaker" people who can't keep the same pace without thinking about their broader relationship or their duty of care. I had a boss who did this on team away days too where they were a triathlete and would make the whole team walk at their pace on walking tours without any consideration for older team members with health limitations. One girl wore the wrong shoes and was limping and bleeding by the end and the boss just totally ignored her.
Fatphobia plays into it a lot of the time too. It's okay to treat people like nothing and lead them into dangerous situations because it's their fault for not exercising more.
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