Peter, I don’t think those quotes contradict each other. You can favor a tax cut while preferring it be coupled with spending cuts–which Friedman would certainly have done–or thinking that it might not be politically practicable.
As it happens, however, I do not agree with Friedman’s quote: I don’t favor any tax cut, under any circumstances, in any form whatsoever. If someone proposed a new tax break for low-deductible health insurance, or the consumption of pornography, or the hiring of lobbyists, I wouldn’t favor it. If someone proposed cutting taxes so that the federal government got only one dollar of revenue each year, I wouldn’t favor it.