Why does this game match solo queuing players with full 5 man pre-made groups in QM

They’re awful to play in on the side of the solo queuing players who’ve been thrown together to spend the next 12-20 minutes getting completely stomped on. Considering the blizzard matchmaking system for HoTS is as bad as any MOBA I’ve ever played there’s just no chance of it playing out fairly. Out of 15 games in the last two days five of them were against full premade teams with the type of synergy and balance you would expect from a group on voice comms. Then throw in 3 or so games where someone leaves in the first minute and you have to try and win with AI it just makes for some horrible, horrible experiences. Would it be so bad to just match the 5 stack with something similar? Even a group of four and one solo queuing player? or a 3 stack and duo? That way the game would actually feel somewhat challenging for the guys in their premade group and wouldn’t be such a negative experience for 5 randoms. Genuinely trying to keep playing this game because I think it’s great fun but these experiences make it real hard to hang around. I understand the need to cut queue times but in plenty of other MOBAS the people who queue as 5 generally have to wait longer so that they’re matched fairly for the sake of all involved. Why doesn’t HoTS?