The basic meaning of the two are the same. However, the first one describes an aspect of the subject "Business Leaders" by using "opposed" as an adjective and "are" as the verb. Saying that they "are" opposed is describing a state of being. Whereas the second one uses "oppose" as the verb, because it is describing an action the "Business Leaders" are taking.
Both the verbs are used in present tense, so they would still be the same.
Thus, the two sentences mean the same thing, the first one is just a more extensive (maybe more formal) way of saying it.