I don't think we look down on larger palettes. On the contrary: use as many colors as your image needs!

But remember that key word: needs. Every color in your image should be absolutely necessary for your image. If you have a 64-color image but can whittle it down to, say, 54 colors without the image looking drastically different/worse, you would do well to aim for the lower color count.

We advocate for intelligent color management, for cohesive palettes, for the idea that you make every decision about color in furtherance of creating a better piece of art. If your image absolutely requires 40 colors to pull off, I don't think many of the posters on this site would give you much crap about it. (They might suggest ways for you to lower the color count, sure, but I would hope they'd understand that their suggestions are meant to be just that.)

Small palettes are good, but they're not an absolute requirement to create or post anything on Pixeljoint. Don't let anyone ever try to tell you otherwise.