About a week ago, Google began sending out a nice number of SSL warnings via Google Webmaster Tools.
Google has paused those warnings because they have caused a lot of confusion within the webmaster community.
Google's John Mueller wrote in a Google Webmaster Help thread:
Thanks for all of your feedback on this! We decided to pause these messages when we saw that they were causing confusion, and we'll work on making them clearer & consider tweaking the criteria for them before restarting them.
In general, while I agree that it may not currently be practical for all sites to serve their content properly on HTTPS, I think it still makes sense for the hoster to make a clear decision: either serve content via HTTPS properly, or not serve content there at all. Serving content via HTTPS without a valid TLS/SSL certificate will result in users seeing scary browser warnings, and avoiding that probably makes sense even if only a handful of users see them.
At any rate, we'll be back, and we'll be watching out for your feedback in the meantime.
So while Google may have been right about the warnings, they were a bit over the top and Google decided to address them.
Forum discussion at Google Webmaster Help.