Messages from Firefox

Is this with all websites/pages, some, a few?

You may have ad/mal-ware. Further information can be found in this article;
https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware?cache=no

Run most or all of the listed malware scanners. Each works differently.
If one program misses something, another may pick it up.

Also,

Go to the Mozilla Add-ons Web Page {web Link}
(There’s a lot of good stuff here) and search for a good ad blocker.

Hi, When I open a tab I get a message from Firefox. How do I disable that? I keep getting messages about racism. Thanks for your help. Jim

see https://support.mozilla.org/en-US/kb/snippets-firefox-faq#w_i-donaot-like-a-specific-snippet-what-should-i-do