The reason everyone believed it was Israel is because they do it all the time. Today they bombed a church. I find it funny (as long as you ignore that these events involve dead people) that Silver here is up in arms for an alleged misattribution when it happens otherwise every day and nobody is bothered. A novel thought: maybe stop bombing civilians and the chance of you unjustly being accused of bombing civilians go…
When Israeli military officials say "this was certainly a Palistinian attack", the news media should be noting cases where they lied about that in the past (eg the death of journalist Shireen Abu Akleh).
Likewise when Gaza officials say the reverse, the same should happen.
I get that journalism will have bias, both personally and based on past actions because they're human and because of basic pattern recognition. But when discussing the facts of an event, it's important to separate what we know (an explosion happened at a hospital in Gaza) and what we're getting from dubious sources (that it was an Israeli airstrike or an Islamic Jihad rocket failure).
In the end, it looks very likely that it was, in fact, the Islamic Jihad rocket. But on day one? No journalistic source should be repeating assertions of blame from untrustworthy and extremely interested parties without the appropriate caveats.