It's all about who's impacted by the protest. These people could funnel the same energy towards a targeted protest against some company profiting the war, or at politicians they disagree with, or protesting at a government building, at a college stifling speech, or at some high profile event or any other legitimate target. You can do something that isn't targeted at everyday people, traps them in the protest, and carries the chance of stopping the delivery of critical services. "Sorry the paramedics couldn't get to gram gram fast enough, but people needed to block traffic for Gaza today" is a bs possibility to allow.