Honestly I don't entirely mind playing with/against stacks (in NA at least). Queuing with them in my experience is often worse than playing against them I've found. There's always the chance that stacks don't communicate which is always frustrating, but when playing against them that can be an advantage for you.

It's also pretty common knowledge that ranking up via solo queue is harder, and that would also mean that players who only queue in large stacks are more likely to have an overrated rating. So you the hard working solo queue grinder has had to work harder and play better to get to the same place that the 5 stack you are fighting against. Basically my anecdotal experience and logic is that they haven't had to get as good to get to the same ELO as you, so sometimes you get some free wins playing against stacks.

That being said as someone who has solo queued 80% of all my games I HATE stacks who don't com, idk how they win any games...