I agree that they can deescalate when they want to. However, the way I understand the defund the police idea was to defund and eventually get their needed funds back with lots of reform. The prospect of funds does change things quite a bit. Always! At this point they're overfunded so no carrot to get them to move forward.
Most "defund the police" opponents I personally know are furious that protesters were ever allowed to enter the building and are demanding to see everyone who did arrested.
It's hard to even get that far at this point. They (and I - I don't want to pretend to be a neutral party here) are still reeling from the idea that you can forcibly enter the US Capitol without being shot dead on the spot. Basically everything we thought we knew about the typical processes of policing is, apparently, wrong.
That's fair. I won't rub salt in the wound; seeing this all unfold on video is way more chilling than I'd anticipated. All I'll ask is that once you feel up to it, you have a candid discussion with someone on the other side of the issue about why they feel such drastic action is necessary.
It's crystal clear that the police have no trouble deescalating violent situations when they want to.