90% of Coop vs. Al games have Bots on your team

Bots are in almost every game and riot doesn't seem to care. These bots always follow the same patterns; ghost and flash; all mid and feeds endlessly, and says the same lines like "WTF", "Push!", "Frozen!", and "GJ!". .

So why can't riot just make a griefing filter that looks for these things and ban them, or just download whatever software they use that are publicly available and create countermeasures? .

This has probably been going on for months and I just feel bad for those actual new players having 4 bots on their team and wasting their time.