Should in-person interview norms apply to video interviews?

1. No. Act like you really want the job and are willing to sacrifice an hour of your time.
2. Yes. We have lowered enough standards in our society.
3. If the potential employee does not respect the hiring process they are not likely to respect the job. But....we can't assume they know better. You must provide direct honest feedback. Explain that there are expectations for employment that begin when they are first interviewed. If they are unwilling to commit fully to the interview process by putting on a clean shirt and ensuring no distractions in the background that they are diminishing their chances of gaining employment.
I have asked this question on a few occasions: "How much time did you spend preparing for this interview?"
Hope this helps.

My last job interview, the interview for the job I have now, was conducted over the phone. The interview was a formality, the benefit of who you know rather than what, and served as an introduction to my new management team. That was back before Zoom, the tech boom and filtering down of video teleconferencing to a cell phone. I didn’t have to wear a suit or be in a professional setting because it was a voice only meeting. That might have been an outlier.

Of course, video interviews should be approached the same way as an in-person interview. Of course, you should wear a suit. It’s an interview. Failing to treat it as a professional engagement makes it easy for the hiring authority to negatively evaluate someone as a potential employee.