Looking at a few entries in Google, it is only those writers who use "sports" for "sport" that write this way.
That makes it correct.
"Sports" is being used like "maths".
To say this is wrong, you'd have to say that the usage of "sports" is wrong since, in the context, "Sports is ..." is right.
Here are some examples. It appears to be prevalent in Canada and north-east US.