I feel like it could be considered dangerous for some people. For someone who faces harassment regularly, taking away the option to block people means making them choose between a) dealing with constant online harassment, or b) leaving the only online community you know. At the very least, this change will be severely detrimental to some folks' mental health, while providing absolutely no benefit to anyone.

It could also be a public safety risk because twitter is a place where many people get news about natural disasters and severe weather. The people who are forced off of the platform because of this change will lose a valuable aggregate of information, and when it gets removed from app stores for violating their TOS (they require that social media services allow blocking), even more people will be without that information.