The practice is discriminatory against anyone who is disabled or has suffered an injury and can't stand in one spot for even a few minutes. Moving to a conference room is moving out of context.
I'm sorry, that's nonsense – in the same way it would be to claim that any meeting where people usually sit down is discriminatory because some people have medical conditions that make that difficult.
Any company with even a shred of positive culture will work around an individual's medical needs. You can all sit down, or some of you can sit. I sit on my desk for most morning stand-ups.
In that case it does not ruin the standup to allow you to remain sitting, or have everyone sitting. Actual standing up was one point they recommended out of multiple and is not necessary for the practice to be useful.
Any company with even a shred of positive culture will work around an individual's medical needs. You can all sit down, or some of you can sit. I sit on my desk for most morning stand-ups.