Well, I think it's true. Gomoku in its standard rules is a solved game, "X", or "Black Stones" has advantage.
But you need know every "surewin"'s moves or you could be blocked
There are like 50 (or more) surewin games to learn and these are very useful like blocks.
In the other hand is "Swap" or "Swap 2" oppening rules, I think are the best rules because, if you play strategic there aren't advantage any side. You could beat programs.
And If there are players that play like progs, the answer is YES, there are plenty of players, but they dont play everydays, they are competitive players. for example: "Attila Demjian", "Zoli", "Rudolf Dupszky", "Ko han Chen" etc etc