I believe they are intercepting and switching petitions to further their left-wing agenda.
I went first to the Law Enforcement Today site (which I found out later is not actually sponsoring a petition for impeaching Trump).
From there I then clicked on a link that sent me to whitehouse.gov.
Where I signed a petition to impeach Pelosi. The next day I got a thank-you email from Care2Petitions, thanking me for signing the petition to impeach Trump instead. I sent them an email to complain and when I checked back it was switched to impeachment for Pelosi. They never answered my message.
I had never heard of Care2 before. I noticed there are six other similar complaints about petitions being switched from impeaching Pelosi to Trump on the site.