Afaik there isn't a Raider PF button and a Normal player PF button, so I beg to differ on that one. Howeverrrrr, yes there is a noticeable difference in the calibre of blind groups early on compared to later down the line. Again, that's nothing to do with evil raiders, it's just a simple byproduct of more skilled players being more likely to have gotten their first clear out of the way sooner. You'll have talented players who waited, but they are the minority and I suspect as more people see this trend, it'll only continue to get worse as people rush to get a kill so they don't have to deal with this.
In my experience at least, if a group's going badly, I'll do my bit to try and engage and coordinate people for that clear. I won't touch DPS for aforementioned reasons but I honestly can't remember a modern Extreme where that's been a problem as long as I can keep people alive and scrape them through mechanics. It's nothing a casual can't do if they have the inclination and motivation.