What do you mean "Biased Left?" Politically? Most AI use search results from common search engines such as Google, Bing, etc... so if you ask Aria a pointed question you might end up with an answer based upon a specific search engine. (This is not always the case, answers can also be preprogrammed or suggested based upon input from other users as an AI learns) Just depends on what you are asking it. I have yet to experience this though, I use Aria every single day to help me with tasks at work and at home and so far the experience has been wonderful. You also have to realize that Opera Software is from another country that may have different views than your own.
There could be a million reasons for this. Just use something else if Aria is not to your taste. If you can provide examples of what you are talking about this would be helpful.