Do note that arbitrarily removing HTML tags can have funny consequences! (Using either their code or mine.)
This is a nothing post. <span style="display: none;">This blog owner is a doofus</span>
As written, the stuff in the span doesn't show.
After removing the HTML tags, you get
This is a nothing post. This blog owner is a doofus
All of this is just really poorly thought out. The blog software *SHOULD* be using a WYSIWYG text editor that does *NOT* allow HTML tags and that, instead, uses pseudo-tags (as does this forum, where we can use [ b] xxx [/ b] tags--without the spaces--to create bold text).
I think I would avoid BlogSpot if it doesn't support something like that!