Saying your position has overwhelming support is a logical fallacy called the bandwagon appeal.
It’s actually an effective propaganda technique. Anyone who disagrees with the author is painted as out of touch with the majority. The same technique is being used to increase support for sodomite “marriage.” Polls clearly show most people are in favor of it, so you’re abnormal if you don’t agree. It makes people shift their opinion to the perceived majority’s, which makes it even easier to sell as the majority opinion.
Well, if the majority are idiots that actually doesn't reflect badly on the outliers.
Thanks for that interesting link on argumentum ad populum. I see the article also calls it the “bandwagon fallacy” among other names. This approach is used often and it should be countered by calling it what it is as you’ve done.
In a similar vein, consider the language used when antis talk about “reasonable” gun control.
If you are in opposition, yours must logically then be an “unreasonable” position. Your opponent has already defined the terms of what is reasonable, so it is impossible to win the debate.
Just by entering the debate on those terms you’ve already lost.