I have a dump email that I give out for all those kind of transactions. It has ballooned over the years so that I am getting about 80 a day and that doesn’t include all the ones Yahoo filters out for me automatically because they are conservative by nature. I do that so every once in a while I mass delete and don’t have to sorry about losing anything.
Yahoo never seems to filter any democrat or liberal mail that I have seen, just conservative ones.
Yes, it is funny how that works. I've had email hosted with a variety of hosting, including Google Gmail and the political bias is clear.