US brokers, maybe. But VT? How does a broker blocking you from trading a very volatile stock change the view if an ETF is a good investment or not? You could also hold VT with a Swiss broker.
Maybe I’m just too calm about this, but as a passive investor I do not really care if they block me from buying stocks that I don’t care about. One could be frightened about the outlook of what they could do, if they have done this. But I think it’s a long way from causing any trouble for the average passive investor.