I don't find it easy to e-mail congresspeople who aren't Michael Capuano

First their web pages do not list an e-mail address. Instead there is a form to e-mail which takes a while to fill out. Second, and much worse, it requires a zip code. In the cases I checked I got an error message, because the zip code was not in the congressperson's district. Ahhh I get it. They want to hear from their constituents. They don't want spam from astroturf outfits (astrospam ?).

OK so how about a web page which gives me the zip codes in a given congressional district. The House web site has the inverse mapping
but when I google "congressional" AND "district" AND "zip" AND "code" I find many opportunities to pay good money for the data (astrospammer prices not concerned citizen prices).

I never understood that that data was valuable.