What you said was both racist and sexist. You're saying that a group of people (based on race and sex) are "not going to ..." do something. Speaking in generalizations using these classifications is generally regarded by most folks as racist/sexist.
It can be tricky though. You might be right, but you'll still be called out for it. For example, the peoples of eastern asia are statistically less tall than their counterparts in western europe. Nevertheless, "asians are shorter than europeans", is still a racist statement.
Unless you can see, as well as explain, how the generalizations you're making benefit the conversation, it's probably best to avoid making those types of statements in the first place.
Racism itself might be "wrong", but that doesn't mean you can't be racist and still be "right" in your assertions. That's the tricky part.