Any CMS, including Joomla, can be used in a way that creates a poor web page.
Here are a couple observations for this situation:
1. It is possible to code a page using CSS positioning so that the H2 is after the H1 in the source code, but appears above it on screen.
2. The goal of H elements is to create a semantic outline of
THE page where that content appears. If this content appears on many pages, it may not be worthwhile to use any H tags for it. Rather you can just style a regular paragraph element to have the same appearance, and use it as a "pre-head" n the page.
3. H tags are so poorly used across the web that they are currently not a very important SEO factor. That's right, not even the "highly worshipped" H1 tag carries much clout on its own. Test it - the glory days are long gone.
I'm not saying we should abandon semantically proper mark-up - far from it. Some day in the {near?) future, all those H tags may be very helpful relevance signals.
[edited by: tedster at 6:23 pm (utc) on May 1, 2010]