Summoners have the highest DPS in the game. The reason people hate summoners was because of the initial parser results which showed them to be the lowest DPS but it didn't calculate the DoTs correctly. Now parsers are working and summoners are finally concluded as highest DPS output out of all classes. Problem is...first impressions last and so a lot of ignorant idiots out there still think summoners are low DPS.

Ignore them. That's all you can do.

Summoners are highly sought after in good groups. They may even be more sought after than bards since they currently do 30-50% more DPS than any other DPS class.