I feel your pain. There could be a whole topic on this. We had parents who would yell run on D3K when 1st was occupied time and time again. If we missed an IF popup they would yell infield fly rule (when it wasn't the right situation). The worst was a group of parent that would stand down the line and yell "miss it" on fly balls. This was 14U TB not rec. We at least put a stop the last thing quickly.Love, love, love the parents on the teams my DDs play for.
However, they will always argue on the side of our team. They'll be yelling "She was safe!!!" when she was out by two steps if it's our team who was at bat. I won't say it's embarassing, but it's bordering on it.
And on the more obscure rules, many of them make up the rule definition on the fly that best suits our team. It's really quite crazy. I've wanted to ask "How do you know?". Guess it's just like discussing politics on twitter. Everyone is an expert on everything.