Targeting something based on race and minority status is not necessarily racism. That’s kind of a bizarre jump.
The groups being targeted with the ban are, coincidentally, the groups for whom smoking rates are highest.
If you want to have the biggest impact, it makes sense to target the groups that are A) the majority of smokers and B) those least well-protected against starting smoking by current initiatives.
FWIW I’m against this ban on pure “people should be allowed to do what they want” grounds, but your specific angle of attack seems ill-informed.