The average person's understanding of bail and the reasons for it is.....very, very low. The fact that the lack of understanding is so ubiquitous doesn't speak as poorly of the audience as it does of how we as a society have messaged it over the years (meaning that we haven't messaged it at all).
Most everyone would agree with the principle of "society can lock you up in prison unless and until you've been convicted of a crime."
Yet we also look at people accused of a crime who are arrested and detained in jail . . . and based on the fact that they are accused of a crime (but NOT yet convicted), we default to thinking that they should stay in jail. Cool, cool....what if they are ultimately found not-guilty? Do we say "whoops, our bad, sorry we kept you in jail for a year, ruining your life, only to find out we had it wrong/had the wrong guy/etc.?" And the response of "well, we KNOW this guy did it, there were witnesses, etc. etc."....again, the one thing we know with certainty is that we don't know everything about the event and its circumstances. Maybe the victim said -- in a voice audible only to the killer and one other person -- "I'm gonna fucking kill you." That changes the self-defense picture. I'm not saying that's what happened here -- I'm simply noting that nearly 100% of the time, "shit that we didn't know about" comes out as the process moves forward.
So, we stick with foundational principles: innocent until proven guilty in a court of law. Bail is to 1) ensure appearance at future proceedings, and 2) protect society from ongoing threats. And understand that it's not really good at the second thing. It's not like someone who is a threat to commit more violence is LESS of a threat if they post $500k bail instead of $250k bail. Other conditions of release are much more effective in that respect (e.g., ankle monitoring and house arrest).
Even bail for smaller crimes can fail in that respect -- look a the asshole going around UT punching people. After the second or third offense in rapid sequence, it seems that the calculus on future threat should be one of "he fucking definitely is," and he should be denied bail or have it set prohibitively high.