There is no reason to believe the Congress is unaware of software and
business patents being allowed.  In fact, in 1999 as part of the last
patent reform bill, it added 35 U.S.C. 273 to add a prior user right
for business methods, because it was concerned that people who had
independently invented a business method but kept it a trade secret
because they felt that it was not patentable would be hurt by others
who might later get a patent on the same business method.

Clearly Congress was aware of business method patents, felt that they
should be allowed, but needed to correct a possible problem.

And it is not reasonable to have a patent statute that lists the types
of technology that is to be protected, beyond broad categories.  By
definition, patents are concerned with new technologies.  It would
punish the very inventors of new technologies if they had to wait for
Congress to list their technology before they could receive protection.