The truth is that it matters for some, and not for others. That is just the reality of it (presumably, you are not particularly interested in being matched with men who do not wish to date multiethnic women or women whose ethnicity differs from their own anyway...). There is certainly much more openness and acceptance regarding interracial dating in this country than in the past, but that does not mean that it is no longer an issue.

You are right that eH is not set up to have the race category accurately represent you. Unfortunately, you can't modify the settings for race yourself (like you can your height setting -- as if that's something that's going to change!), or else it would be easy to change it periodically to see if doing that brings in more matches for you. And, it's unfortunate that--as long as race is part of the profile--you can't select multiple options, especially since being multiracial is so common.

What you can do is express your own openness to being with men of different races (e.g., indicate that race doesn't matter in your preferences). That will at least maximize the chances that men who are open to dating women of any race will be in your match pool.

The other thing to keep in mind is that more matches doesn't necessarily mean better matches, especially if the process is weeding out in advance men who are not open to dating you. Assuming you have a well-written profile, I can't imagine that the matches you do receive won't find you interesting (or beautiful), so you may still end up connecting with quite a few interesting men even with your smaller pool.

I wish I had a better answer for you!