My brother coaches kids football but he manages to do it without being an arsehole and will actually listen to parents concerns about anything and is generally encouraging towards all the kids, yes it can get competitive but not to the point where any of the kids "shrink" because of how he is talking/shouting at them
That’s great. To be fair, the majority of coaches are good people who care about the kids on their team, and will listen to parents concerns - although this doesn’t necessarily mean they will act on them - it depends if the concern is reasonable.
But what is not ok is for a parent to publicly challenge a decision. Sure, come and have a quiet chat about any concerns, but your brother (or any other volunteer coach) should not have to accept parents criticising them from the sidelines, or ‘taking them down a peg or two’. Most coaches are only doing their best (and of course have different levels of ability/experience) and some parents can be very pushy, or have a very inflated opinion of their child’s ability. No matter what a coach does, it’s usually wrong in someone’s eyes! I know this from experience - my DH was a coach for 8 years, and I often went along to help. Some of the behaviour from parents on the sidelines was truly appalling.
With regard to shouting, no coach should be shouting (past the fact that they may have to raise their voice to be heard from a distance). But if it’s that bad, why has the OP let her DD be scared for a whole season? Surely they should have raised this, or left, a long time ago?