It's not the suicide itself that is fishy. I'd imagine most sex fiends looking at a lengthy prison term get suicidal really quick when the reality sets in. It's the circumstances and negligence that allowed it to happen, that makes it suspicious. Why was he taken off suicide watch? Why did the guards not follow protocol? Why was his cell mate moved at the last minute, leaving Epstein alone? Where is the CCTV footage? This is the first suicide within the walls of that prison.
On top of all that, we've got a shady motherfucker presiding over the autopsy findings.
The whole thing stinks, and this is one time where the non-conspiracy folks are struggling to find rationale at how this happened. They practically have to come up with conspiracies to make it all look innocent. The conspiracy theory that this was purposefully allowed to happen for whatever reason, and had all the pieces in place to make it happen, makes far more sense than the "nothing to see here" explanation.