I would not attribute Epic's review ratings to "trolls", but I also don't believe they are really a fully accurate measure of Epic's public perception (or any theme park for that matter). As a general rule for any public rating system, people are a lot more willing to go out of their way to post about a negative experience than a positive one. While Epic does have a lot of strengths, one of the biggest issues it has been having is downtime for major rides.
What I suspect is that a lot of these reviews are being written while a ride is experiencing a "Delay", and frustrated guests are stuck waiting in the queue for an extended period of time. When you're stuck in line like that, someone might see writing a negative review as a way of "getting back" at Universal, regardless of whether the rest of their day went smoothly. Obviously, downtime is still an issue that is pertinent to be addressed, but it is also likely skewing some of the review scores we are seeing.