htaccess file on Apache server and blocking back link tools

[nesir]

Hi guys ive read alot in the subject and the risk certianly outweights the cons for me im trying to use my htacess file to block semrush ahrefs and all the big backlink checkers as i have recenlty seen people getting duplicate links to what i have also being scanned by bots that steal my bandwidth on my server . Ive tried many variations of this but it soesnt seem to be working can i dont know too much about mod re writes syntax , here is what i have :

RewriteEngine on
RewriteCond %{HTTP_USER_AGENT} ^rogerbot [NC,OR]
RewriteCond %{HTTP_USER_AGENT} ^exabot [NC,OR]
RewriteCond %{HTTP_USER_AGENT} ^MJ12bot [NC,OR]
RewriteCond %{HTTP_USER_AGENT} ^dotbot [NC,OR]
RewriteCond %{HTTP_USER_AGENT} ^semrushbot [NC,OR]
RewriteCond %{HTTP_USER_AGENT} ^gigabot [NC,OR]
RewriteCond %{HTTP_USER_AGENT} ^AhrefsBot [NC]
RewriteRule ^(.*)$ http://example.com

Not to me this should redirect the bots away to another site yet it doesnt am i ovelooking simple mistake here?