Shari will let you get away with "bitch" (it is, technically speaking, accurate) but not little and the only whining you'll hear is her magnetic accelerator pistols.

Oh, wait, you said heroes. Never mind, she's not a hero. ^_^

Uhm...not really. Some I think probably qualify but the vast majority not really (even the ones with bad backstories). My first RP hero character had to go through an awful experience to gain his powers but he doesn't whine about it.

I find that there is more whiny villains then heroes

I opened the video expecting to hate it. To my surprise, it was pretty good. There are a couple of points I'd dispute, but they are minor and not worth mentioning here.

There is an unspoken contract that exists between those who create and those who consume. One of the caveats in this sacred bond is that the consumer is free to interpret the creation in any way they like. That interpretation is colored by the experiences, prejudices, and expectations of the consumer. As a result, the creator is often shocked at the response to their work, especially in those rare cases where the creator has poured some deeply held personal value into the creation. It is often a shock to learn that everyone has different values and as a result, the consumer sees in the creation some value the creator never intended the work to portray.

When the creation is a movie, the team of creators who pour their time, effort, and emotion into the work is vast, but so is the audience. The contract between the creator and the consumer is stretched very thin, and sometimes shatters under the burdens of all those competing value sets. When the movie features someone or something so iconic it has deep symbolic worth that crosses over multitudes of competing personal value sets, it can be nearly impossible to truly do the icon justice because the movie only reflects the interpretation of the creation team, a team that often has no genuine connection to the creator that gave birth to the icon.

In short, I think the self-proclaimed "Nostalgia Critic" is asking the wrong question. A better question would be, "Why do so many people come away from comic-based hero movies convinced that modern superheroes are whiny bitches?"

It's not really about the icon. It's about the unspoken contract between the creation team responsible for the movie and the audience that consumes it.