Yes, it might be a crime
The relevant legislation is the Computer Fraud and Abuse Act which, among other things, makes it a crime for a person to "intentionally accesses a computer without authorization or exceeds authorized access, and thereby obtains— (C) information from any protected computer;"
A "protected computer" is ...
There are three main aspects to this:
Its their website, and their terms of service. They can enforce those terms, or change them (in some appropriate manner). You have no recourse if they remove you, block you, or delete your account, for example. That's the measure that you would probably have, virtually every time.
To claim damages, or litigate beyond ...
I see no contradiction. It says that
you agree that you will not use this website or our services or
applications for chain letters, junk mail, "spamming" or commercial
solicitations or to send any message or Content that
[is clearly bad, as extensively described]
As a customer I can use the site to search for suppliers of bolts and request a ...