Depends on the type of Buddhism... Theravada or Mahayana?
Original Buddhism, Theravada is what you consider "pure" Buddhism, as in those teachings passed on by Buddha himself. It is highly monastic and in many ways difficult for the layperson to follow. Especially given it was somewhat iconoclastic
Mahayana Buddhism is far more flexible in adopting itself to local traditional and cultures, believing that enlightenment could be achieved in many ways, and where quite open in adopting multiple local religions into it's fold. That also made it more popular and widespread.
The so-called mixing of Buddhism and Taoism is perfectly in line with Mahayana thinking. There is nothing strange about it. Taoism in itself is an interesting blend of folk religion, animism, and existential philosophy.
Don't even get me started on zen. Lol.