Sending correspondence to your legislative representatives about your opinion on a matter is NOT unsolicited email.

You are misinformed on three points.

It doesn't send anything but assists visitors to send on their own.

It is not unsolicited communication.

Politico is not an unbiased publication.

I mean, in the sense that your comment here was unsolicited, and thus spam, I suppose one could make a semantic argument? But generally "unsolicited" means that it's outside normal communication expectations: we expect people to post on a forum even if their opinion hasn't been explicitly solicited, and we equally expect people to communicate with their representatives.

That depends on how many comments you post in a short time and how repetitive they are. If it looks automated then I think it would be considered spam, at least informally.