OP - what do you propose should happen?
There is no easy solution. It's nothing to do with who 'deserves' to be in school or not.
Critical workers who have to work out of the house need the childcare aspect of school in order for our essential services and industries to keep going. In a pandemic unfortunately some jobs are going to be classed as more essential than others.
Teaching and school staff do need some level of protection. Overcrowded classrooms with no social distancing, no masks, etc have ended up proving to be a difficult area for this. Covid is in schools and spreading quickly in many of them. Unsurprisingly children do catch covid, even if they don't get as ill with it overall, and they do transmit it. The unions finally got some information that actually showed this, information the government were not overly keen to share.
Therefore school staff need to be able to access the basic protection of SD, etc. In order to do this we need to reduce class sizes. We know we can't shut to all as that means the economy cannot keep working.
Parents ideally should only be using their school place if they are a critical worker and there is no one at home to look after/supervise their child. Obviously there will be some who really push this and could have their child at home - yes, they may be working still if at home but then so are many non critical workers. However, it's very hard for schools to prevent this. We have to trust the parents to do the right thing where possible.
Obviously vulnerable children need to be a priority. Most schools are very aware of their vulnerable children, even those where it is less obvious. They are in as they deserve to maintain the 'safe space' of school in lots of situations.
Some children under the vulnerable category need to be in due to their specific needs. These obviously need to be higher priority to those who can cope with remote learning fairly well, even if it's not ideal.
So OP, what do you propose we do that still helps reduce the spread of covid and still helps to protect school staff, children and parents from this virus?