The veil of anonymity online brings out the best and worst in people, but usually you only remember and notice the worst of the bunch because they make a bigger impression. The fact of the matter is that you have to learn to grow a thicker skin to deal with these types of people, and find some like-minded people you can get absorbed with so you have less run-ins with trolls. Problem users do not discriminate based on server settings, population, or even games for that matter. You will have bad eggs everywhere, but the concentration of "trolls" on higher rate servers stems from three issues; the lack of accountability, the lack of permanence and the type of gamer each rate setting attracts.
Let's kick it off with the lack of accountability that comes with high rate servers. High rate servers generally have a setup where it's very easy to get a character to max level with quality gear, comparatively speaking of course. It usually doesn't take too long to get to a point where you are at least competitive with veteran players, so you have a system where there's very little investment into a character. This lack of time investment creates little deterrent for users to behave; they can simply change their IP (if necessary), make a new character and start over again with little headache. On a lower rate servers, of course there isn't much accountability for low level characters, but once people start getting gear and leveling up, there's a serious time investment placed into these characters. Players will not want to lose their time investment, thus there's a reason to behave; you misbehave, you run the risk of losing your time investment. Low rate servers by default create this level of accountability, which means you will have players more inclined to follow the rules and put on a better public face. This is generally absent from higher rate servers.
The whole accountability issue is also tied into the general lack of permanence associated with high rate servers. There is usually a significant turn over rate in the high rate server community, both in terms of players and servers. Many high rate servers do not last long, die out due to corruption, lose their appeal or simply shut down due to a variety of factors. Players often do not have any allegiance when it comes to a high rate server either; there's so many of them out there it's not difficult to find a replacement. Due to high rate players not feeling tied to their characters, they often find it easy to get up and migrate to a new community. Essentially, high rate players in general feel no sense of allegiance to their server, thus reducing the necessity of keeping a good reputation. In the end, you have a situation where players do not have any reason to be tied to any single community since high rate servers tend to cater more to migration, which is due to the lack of accountability generated by the easily earned progression in the game.
Finally, we're left with the topic of what sort of gamer each game type attracts. High rate servers are generally focused exclusively on PVP elements and socialization, however keep in mind this is not to say that low rate servers neglect these elements. High rate servers put little to no emphasis on progression, with the end game being simply being mindless PVP. Low rate servers require a heavy time investment into progression to acquire quality gear that allows you to be competitive in PVP and WoE. You also have a strong focus on WoE due to the fact that the rewards are meaningful with such low drop rates. High rate servers are always going to attract people who want to mindlessly PVP, those who just want a quick fix of PVP adrenaline, and those who don't want to put any effort into the game. Low rate servers are generally going to attract those who want a challenge, those who want to build up a character and compete against others in a perpetual race to achieve more progression and those who want meaningful PVP experiences. What you have is a separation in the caliber of gamer; high rate players are casual gamers, low rate players are more hardcore about their gaming.
In the end, I simply believe that the caliber of gamer each gameplay type attracts is what causes this perception of "trolls" being more populous on high rate servers. Low rate servers have more accountability associated with them due to the time investment required to stick around. Quality low rate server are also few and far between, thus creating a situation where gamers won't want to lose their social status or ability to connect to the server. In contrast, high rate servers simply do not require much of a time investment nor are they as hard to find. It will always be a matter of what type of person plays each server; if you want a more community feel, you're better off playing low rates.
There's also a host of other issues associated with high rate servers, but I'll leave them out simply due to their relative lack of relevance, and in the hopes that someone will actually read the wall of text I wrote.
