I know I'm preaching to the choir, but, hey, Choir: maybe some of you can preach to the perpetrators. Double quotation marks have several uses: to show that someone is speaking; to show that a few words have been quoted verbatim; and to show that the words so-called are implied.
I shall give an example of the latter: I believe that these two sentences have almost the same meaning:
We sell so-called fresh shrimp.
We sell “fresh shrimp.”
Sadly my favorite supermarket thinks that the second sentence means:
We sell remarkably fresh shrimp.
Languages evolve. Even punctuation evolves. The trouble with this new use of quote marks is that it directly conflicts with an existing use, and for those of us aware of the contradiction, it fails to accomplish its intention. For example, I find it hard to believe that my supermarket's shrimp is really fresh; too bad I will never find out. I also think the realtor who brags like this on his billboard fails to convince me:
I “sell” homes.
I find it hard to stay off land when I'm asked to do so in double quotes:
“Stay off the grass.”
And I am not attracted to a restaurant whose billboard says:
“We serve vegan food!” (Who said that?)
This new use of double quotations could be welcome in English as soon as we expunge all of the directly conflicting usage. Which of course will never happen.