It doesn’t Who said it did? The Supreme Court decided to make gambling legal, not Congress.
A lot of things aren’t good for America, alcohol, cigarettes, legalized marijuana, etc., a lot of people legally gambling now were gambling illegally prior to it becoming legal in their particular area.
The US is one of the few countries that has any limitation on sports gambling, casino gambling outside of Las Vegas and Atlantic City has been widespread for years.
I don’t see any difference in sport gambling versus casino gambling .
“How does this make America better?”
After the next Arnold Rothstein fixes a Stupor Bore not too far in the future, people will stop watching, and that can only be a good thing.