Alan Watts appears to be a renaissance man that is not feeling constrained by any religion or philosophy. You can read general history and maybe get clues to who he was at
here is an excerpt
"Alan Wilson Watts (6 January 1915 – 16 November 1973) was a
British-born philosopher, writer, and speaker, best known as an
interpreter and populariser of Eastern philosophy for a Western
audience. Born in Chislehurst, he moved to the United States in 1938
and began Zen training in New York. Pursuing a career, he attended
Seabury-Western Theological Seminary, where he received a master's
degree in theology. Watts became an Episcopal priest then left the
ministry in 1950 and moved to California, where he joined the faculty
of the American Academy of Asian Studies.
Watts gained a large following in the San Francisco Bay Area while
working as a volunteer programmer at KPFA, a Pacifica Radio station in
Berkeley. Watts wrote more than 25 books and articles on subjects
important to Eastern and Western religion, introducing the
then-burgeoning youth culture to The Way of Zen (1957), one of the
first bestselling books on Buddhism. In Psychotherapy East and West
(1961), Watts proposed that Buddhism could be thought of as a form of
psychotherapy and not a religion. He also explored human
consciousness, in the essay "The New Alchemy" (1958), and in the book
The Joyous Cosmology (1962)."
Watts proposed that Buddhism could be thought of as a form of psychotherapy and not a religion.
So if this is what he thought, he may have not taken an eastern view of making peace with the eternal within as Buddhism proposes. He may have seen Buddhism as a means to a joyous life.
To me, what I think about Buddhism is inconsequential compared to how I practice Buddhism. Not knowing him personally I would not know if his irreverence was a way past dualities that disguised a heartfelt practice.
It reminds me of the story of the zen master who laughed at 4AM in the morning every morning and awoke the whole sangha. Students would ask him why he was laughing but he would just laugh more. Even approaching his death bed he would not vocalize a reason.
After the master died his students searched through all his papers searching for the reason of his laughter, but no clues. I guess the zen master had the last laugh!