I find it really odd all these people who find it rude not to have the camera on. I can only assume they have never really teleworked until lock down.
I've had 15 years of it. We've only recently switched to having cameras on and that's mainly so we can see a friendly face. We will often switch cameras off once the meeting starts properly.
Most of my meetings are working meetings so I will be editing a document rather than a talking shop so I will be camera off. I've lost access to both the computer room and the dining room table so the laptop will be on my knees with the camera at bust level. I could tilt the screen but that would give a lovely bottom up view of my double chins, so professional!
Most people are not working in an home office environment while the rest of the household are out- they are struggling for work space and bandwidth.
It's not like being in the office. Firstly you don't see yourself. It would be unusual to have someone in your personal space to give the same view as a laptop camera. The point about not being able to make eye contact is an interesting one and I wonder if it is one reason I struggle with camera on.
Also backgrounds don't work for everyone. I turn into the invisible woman with part of my face or glasses intermittently looming into view (I have background envy)
I think the insistence on cameras on is poor management. Fair enough, you've not been trained, remote management is a skill set and this is an unusual time.
My husband works for a big multi-national with multi national teams. He spends a good chunk of the day in project meetings with people in other countries. His organisation doesn't have cameras on yet he has been perfectly well managed by people who he might only normally see once or twice a year.
As for those of you who insist on professional standards I hope you have performed all the H&S checks and provided desks/chairs and such like which homeworkers are entitled to. (It's a ball ache, we looked into it for my husband to formally be a home worker but we couldn't make the home office standards.)
Or you can acknowledge we are in a pandemic and we are in an emergency situation and perhaps cut people a bit of slack.