No. What is not allowed is calls for genocide ("From the river to the sea") and support for terrorist organizations.
And yes, if you are a guest in a country, supporting genocide and terrorism can get you deported.
But the police has been extremely lax in enforcement. These protests still basically always have these characteristics and there is no action by the police.
It is pathetic.
> is considered to be supporting Hamas.
No it is not. Even if it almost certainly is. These protests used to run almost daily, and were often allowed to proceed even if actual calls for genocide were included.
And of course you are also wrong on the content: those accusations are largely untrue, and Israel is an absolute leader in avoiding civilian casualties in urban combat, achieving a 1:1 ratio of civilian to combatant deaths, whereas the world average is 10:1. And this despite Hamas's openly stated and obviously carried out policy of creating as many civilian casualties in their own population as possible.
And no, calling for genocide does not become legal if it rhymes.
Protesting against Israel's carpet bombing and mass starvation of civilians, targeted missile strikes and sniper strikes on journalists (more than any other war in history and there might not be any left by now) and so on is considered to be supporting Hamas. Because if you weren't a Hamas terrorist, you'd support everything Israel says it does to get rid of Hamas. That six year old girl and the paramedics trying to save her? All Hamas. The flour massacre? Hamas. Journalists? Hamas. I'm skeptical that you haven't seen this rhetoric constantly since Oct 7 2023.
Are you aware that people were chanting "from the river to the sea, Palestine will be free", because it rhymes, and they were not chanting "from the river to the sea, let's gas all the Jews again"?