I don't quite think people are against queuing with a few friends, but against this idea that they could be going up against a team that has an 8 man elite premade all in voice comms communicating well. I can't say how real this usually is in Frontlines currently, but it's somewhat understandable to dislike that idea even if it's a bit of an extreme case.

Unfortunately there's not currently a better way to communicate and I'm not sure if there could be one, but having to read text directions in the heat of battle isn't exactly easy.