What’s The Point Of Behaviour Score?

This isn't just a general complaint about how behaviour score doesn't do anything, because we all know it doesn't. What I'm wondering is why?

Why do icefrog keep the current state of behaviour score and how it works and not do anything to improve incentive to not be toxic as hell? As someone who maintains 10k behaviour score, what incentive or motivation do I even have to continue doing that? because as it stands almost every game I play is "highly varied" and I regularly get called all manner of toxic and bigoted shit, often being targeted for my gender or race by people who I can be pretty confident will never be punished for it. So you don't get rewarded for playing nice.

Nor do you get punished for playing poorly, having blow 1000 behaviour score or something laughably low actually mutes you, but that means you have to consistently be a toxic person for MONTHS on end to even come close to that. So why would anyone ever be afraid of that?

I love DotA2, but anybody who claims it isn't one of the worst communities in gaming, is too far gone to have an objective fact based discussion with. I would go as far as to say your average preschooler has more manners and communication skills than the worst person in any given dota game. Is there anything that can meaningfully be done to combat that?

Because as it stands, the logical response to the current systems in play is "well, if there's no punishment, why not start screaming the n word back at this guy?" and evidently a LOT of people have taken that message away from it.

TL;DR: Behaviour Score is so ineffective in what it aims to do that it arguably has the opposite effect, and proves how people can act toxic with no punishment. Is that the point, or is this something that can be fixed?