I don't know what the limitations on pinterest ads are - sometimes you try and cram in copy to get the gist of what you want to say in scannable form so I wouldn't read too much into the correctness of the english.
Let's look at the wording again:
JW.org has the Bible and bible based study aids to read, watch, listen and download in 300+ (sign included) languages. They also offer free in home bible studies. All at no charge.
The application of the first sentence's verbs to both "Bible" and "bible based" leads to the incorrect statement that the Bible is available to "read, watch or listen to" in many languages including "sign". The second and third instances of "Bible" are not capitalized. "Bible-based" is not hyphenated. There's no "to" after "listen". "Sign" is not a specific language (especially when not capitalized), and its parenthetical location in the sentence is dubiously grammatical. "In-home" is not hyphenated. The last sentence is a sentence fragment.
Are you really telling me you think someone at the Society wrote that?