Odds are, it's to avoid Cross Site Scripting attacks.
http://en.wikipedia.org/wiki/Cross-site_scripting https://www.owasp.org/index.php/Cross-site_Scripting_(XSS)
http://en.wikipedia.org/wiki/Cross-site_scripting https://www.owasp.org/index.php/Cross-site_Scripting_(XSS)
Test: <>
Edit:
<p>Test: <></font></span>
Yep.