Risky people are more likely to make poor decisions and contract any kind of infections, including STDs. Probably they experience more stress and frequently deal with that by getting pets that infect with Toxoplasmosis.
But your point is still valid. The conventional wisdom on why risk-taking people might be more prone to toxoplasmosis in the first place is that they're more likely to eat undercooked or other ill-prepared meat, which is actually a much more significant risk factor for toxoplasmosis than cat ownership.