Tbh, they can set up their own group how ever they like. I think you are the one in the wrong for thinking that they are bad people for not carrying you.

Maybe they do teah other times, they could have had a long day and just want smooth runs. Maybe they just want smooth runs regardless of thier day. It not upnto them to have frustration in their relaxation time just because you want a ggod group to carry you. That you think so is more than a little selfish. Yes setting up your own team is a solution, and the best one. Clearly state what you are looking for and stand by it. If enough are looking for that, you will get a group.

Do you have any idea how annoying it is to have a couple of people who are looking for a carry to sneak into your group, that you spent almost an hour setting up, only to make it fail and disband? Do you realize how common it is for this to happen?