User blog comment:The Milkman/The Definitive Mass Effect Experience?/@comment-68.99.63.38-20121104060137/@comment-899316-20121105012439

Lily, BioWare ceases to be a group of "storytellers" as soon as they start selling their story. At that point, they become businessmen, and the story becomes a product. If the market finds what they see as faults in the product, they have the right to mention it to the producer of that product. Then, the product is either amended to meet the desires of the market, or the market loses interest and the product disappears. For example, I personally was quite upset by the ending to Mass Effect 3, and I felt that I may not have gotten enough for what I've paid them over the years. If I feel that I have been ripped off, then I have the right to voice my complaints. With their market in an uproar, BioWare chose to amend their product with the Extended Cut, so that it would meet the demands made. Had they not done so, they would have lost customers, and thus money.

TL, DR - Money is involved, so people both can and should complain.