Thinking something and saying it are two different things. Explaining this fact necessitates saying it, but we're in a different context to the original. I see no insincerity in that.

"I never should should have said it, whether I still believe it to be true or not" might have been better, but I think it's presumptive to assign it to insincerity.

You could say the same for "smacks of x" being proceeded by the word "respectfully" - why say "smacks of" with its derisory connotations, when you could say "seems"?