I have the exact same problem. Way too many pirates. There weren't any in my home system at the beginning, but every other system around mine has some. I have explored a few dozen systems, haven't found any other empires' planets or bases yet. But by getting information here and there, now I know of 13 Empires, all of which (but the Guardians) hate me, and a whopping 16 pirates. Only two pirates have really caused me trouble so far, but all of them have from 2x to 16x more ships than I can afford to have, and some pirates control up to 27 colonies to my 3. And everyone hates me, since the stances and orders we can give to our ships are primitive and my stupid ships attack every pirate they see, even those who haven't done us any harm yet. I don't think I can win the technology race against them either, since they already have quite a few techs that I don't have, and I can't expand fast enough because they keep raiding any system that I leave with as many ships as I have in total.
In short, there are way too many powerful pirates on the default settings. If I played as a pirate, it may have been good to have many of my peers, but as a regular empire I am not sure there is a point to keep playing.