I'm uncertain whether they were access denied for this specific reason, but it seems plausible considering their lack of speed and the fact that they didn't engage consistently, such as Geeta R. and their numerous other accounts, who were active 24/7 (bot). The snapshot is from 2015, this is 2011 vocab.com:
https://web.archive.org/web/20110203063021/http://www.vocabulary.com/ (and this is end of 2011:
https://web.archive.org/web/20111202175512/http://www.vocabulary.com/).
Indeed, the in-list chat feature had been removed before my tenure at Vocabulary.com began. However, we still utilised a forum chat located below articles, as well as an "About Me" section where users could compose entries of up to 1000 words. Additionally, we had the option to list favourite and least favourite words, along with explanations for each.