I think it's only an editor choice
, unluckly .
Exactly, and despite the fact that DMOZ tries to select edtors well they are sometimes corrupt, and will sometimes only accept sites if they get paid to do so.
This is particularly common in the web design and hosting categories.
I don't want to suggest that this is what happened to you, I have no evidence to point to that conclusion. What I'm saying is that this is just a fact of life we have to work around. No site has an obligation to include any of our sites.
Google has been sued for penalizing a SEO site that sold ways to improve page rank. The complaint was that given Google's market share their penalizations are an unfair damage to business.
Google won that suit by claiming their page rank is free speech.
I expect more battles in the future about inclusion, but for now we need to live with the status quo.
And the status quo is that commercial sites (especially hosting and web design) are better off using commercial advertising instead of free SEM.