BuddyPress.org

Try reading up on enabling a third-party provider for WordPress’ embedding capability:
https://codex.wordpress.org/Embeds#How_Can_I_Add_Support_For_More_Websites.3F

If you want to use Wistia code, which I’m guessing you need to use the “ or “ tags, you’ll need to bypass the activity filters that are in place by default, so malicious content will not get the chance to be executed.

If you trust your userbase, you can disable these filters by reading this:
https://buddypress.org/community/groups/how-to-and-troubleshooting/forum/topic/make-users-able-to-use-and-in-their-posts

Or this:
https://buddypress.org/community/groups/how-to-and-troubleshooting/forum/topic/embedded-video-in-forums-and-streams/

If you’re planning on just embedding the Wistia video on a blog post, just enable some form of WordPress plugin that allows you to embed content like this:
https://wordpress.org/extend/plugins/embed-object/