I found that hard to believe as my Thai wife and I were married in Canada 17 years ago 2006, and I got a one year multi Non O Visa from the Thai consulate in Vancouver as I was traveling back and forth for the first 4 years, then when I moved permanently to Thailand in 2010, I applied and received an Non O extension.
The Process I had to do in Thailand was to go to the Canadian Embassy, get a statement that I am able to be married, went to MFA and got our Marriage License translated to Thai, the went to our local Amphur (Thong Lo) and registered our marriage, then I had no problem getting a Non O based on marriage extension.