Know your history.....
The word "pool" means a collective bet, or ante. Many non-billiard games, such as poker, involve a pool but it was to pocket billiards that the name became attached. The term "poolroom" now means a place where pool is played, but in the 19th century a poolroom was a betting parlor for horse racing. Pool tables were installed so patrons could pass time between races. The two became connected in the public mind, but the unsavory connotation of "poolroom" came from the betting that took place there, not from billiards.
And before that from the 1880's to the 1920's Billiards was a respected Gentleman's past time. It wasn't until Proabition when Gansters and their type ruined everything, much like today.