There is indeed "unrest" in the south of Thailand, principally the three provinces of Yala, Pattani and Narathiwat, not in the tourist areas like Phuket, or Krabi. Almost 3,000 people have been killed in this conflict in the last 4 or 5 years including soft targets and symbols of central Thai authority - teachers, Buddhist monks, members of security forces, and local Muslims. Linguistically, historically, culturally, and geographically the deep south is distinct from the rest of Thailand. This, coupled with poverty and other factors, fuels the conflict.
I have never heard of tourists being targeted. Attacks on tourists are unusual, and hence widely reported when they do occur. Generally Thailand is thought of as being a safe country to visit. As for being friendly, I guess that is true to a point. If in trouble here, I think you would find it easy to get help. And motorists and motorcyclists are much more likely to offer encouragement to a cyclist than any of the aggression sometimes written about by BF members in other parts of the world.