The legal concerns they express are valid.
What legal concerns? There is nothing illegal about Bitcoins. Stating otherwise is pure FUD. Treat them as any other kind of non-fiat donation. I donate my underwear and even cash anonymously to the Salvation Army, and then take a tax deduction for it, as do millions of other people. Bitcoin donations are no different.
I suspect you're joking about the underwear, but that is non-deductible if used.