Group rides are good for all the excellent reasons noted above. Don't make your decision based on one bad experience.

I ride alone when I commute (3 times a week) but ride with others on Tues./Thur. evening club rides and for sure on weekend rides. Sometimes I get dropped but usually not. If I do get dropped, it's not tragic.

Regarding "dangerous" riders, not all of whom are newbies, they are quickly identified by the "group" (in my experience) and either learn how to ride safely or are expelled by the group.

Rick / OCRR