I do not know specifically about “adwords” but..
My app was denied by google adsence, BUT when I read the rules .. it said you don’t need to sign up for multiple accounts, once you have an account on 1 site, you can just use the same code on all sites and content will be auto matched. Sooo It is possible that the gambling sites that have this feature, signed up a non gambling site first.
Also.. here’s a funny quote 
(made me laugh anyway..)
Issues:
– Gambling-related content
Further detail:Gambling-related content: Google believes strongly in the freedom of
expression and offers broad access to content across the web. without
censoring search results However,. Google policy does not permit the
placement of Google ads on sites with gambling-, casino-, or
lottery-related contentWe have found your site to contain content of
this nature. Please review our policies
(https://www.google.com/adsense/policies?hl=en_US) for a complete list
of site content not allowed on web pages.
So ummm.. we belive in it, we just dont allow it 