Question SEO <h2> <h3> tags

Hi,
I have created post that included <h2> and <h3> tags using an html editor and inserted that into the kunena post but it showed the tags.Obviously, using these tags are highly recommended for better seo.
I used the code and inserted both the content and the html code between the <code><code> within the kunena as a test to see the results.
This is what it looks like and it is not the way i want it for it does not show the desired h2 code in the content.

www.bayoubuzz.com/forums/gun-control/154...nd-more-victims#1542

This is the html code i inserted. So, I am wondering if the kunena code editor not work or if kunena does not allowh2/h3 tags within the posts.
<h2>Gun control, Las Vegas shooting&mdash;debates&mdash;media, Congress, social media, republicans, democrats</h2>
<p>There are competing arguments as seen on twitter:</p>
<p>Every other country pretty much prohibit their residents to buy guns used during active warfare</p>
<p>or</p>
<p>How about Chicago? That city has strict gun control, but 2,900 shootings just in 2017.</p>
<p>or</p>
<p>Or as Jimmy Kimmel, in blasting the "nuts" who tell him not to discuss gun control: "In your heart, you know you bear some responsibility"</p>
<p>or</p>
<p>As Rep. John Lewis has said recently, &ldquo;How many more dead bodies will it take to wake up this Congress?&rdquo;</p>

Kunena editor is a bbcode editor, so it doesn't support html tags.