Wow, was he ever wrong on that one. I'll tell you, though, I met an Afghan fundamentalist who was a Taliban (but not one who was out fighting jihad) before he was a fixer for journalists to meet and interview Taliban 'warriors.' he's the guy who theoretically saved David Rohde after they were captured by Taliban and taken to Pakistan, in captivity.
So I can understand where Ronald Reagan got his view, they are devout and pleasant toi speak to. What RR didn't get was they're Islamists and jihad's their game. Violent or non-violent, all practicing Muslims are jihadists, by definintion. They also recognize that Islam is incompatible with our Constitution. These are the things RR would not have understood at the time, I suspect.