Why do enemy bots/minions seem stronger than team bots/minions?

Ever since I first started playing, couple years back, I noticed that it seems in no matter what type of match you're in the purple minions are always stronger. I guess that would make sense when they spawn super minions, just because they have robot attachments and not weird barrel/mace configurations like the blue minions. But it seems like the purple ones always gather a big swarm no matter what. I understand that when one teams minions are more sparse, and there's a mob formed, that it could create push back. But no matter what side I'm on, it always seems like purple minions always win over blue. Does anyone else notice that?

Also, I just played a custom 3v3 game just to relax a bit. I just took whatever randomly popped up for bots and switched ALL of them to intermediate. So my team was myself as Lissandra, Karthus, and Brand. The opposing team was Annie, Kog'maw, Soraka. I made sure all of them were intermediate so it was even. I took mid because I was trying something out. Brand was top vs Soraka, I was mid with Annie, and Karthus was bottom with Kog'maw. And, shocking to me, Karthus and Brand fed the whole game. There was even one point Brand bot just came back to life, I tried to catch up so we could team up on the mob of three. But he just ran straight ahead, right into the group, and got himself killed!

I've had several custom games the past week where it seems like the enemy AI is always smarter than the team AI. I asked my friend if he noticed that, as well, as we usually play custom matches when he gets the chance to get online. And he told me that he, also, noticed that the enemy champions and minions always seem stronger and wiser, no matter if he had it 2v2-5v5 or a weird mix like 5v3 or something. I understand that maybe because of it trying to catch up with the fact that there's a living human playing as well, but if that's what it does then it's stupid. MAYBE give extra strength to one to match up with the one enemy human. But otherwise, if that is the case, that would be ridiculous.

So, apologies if this is in the wrong section and for how lengthy it is. If anyone felt this too or what have you, I'd like to know. I'm really curious about this. Thanks much.