They believe the suspect burned down the synagogue. But more is needed for it to be a hate crime. They would need to prove that he was motivated by hatred rather than any other type of motive.

A Sukkha is a temporary structure. What valid reason exists to burn down a temporary structure? Being a temporary structure, a Sukkha will be dismantled and taken away in time… Why burn it? It will go away of its own accord.

The Synagogue burned because, apparently, the suspect lost control of the burning down of the Sukkha… But why burn down the Sukkha in the first place?

For myself, I’m perfectly willing for the arsonist to be mentally ill and, therefore, not responsible for his actions. But that just places the blame — and the hate — somewhere else. What other reason could exist?