Again I’m not saying that religion is better or worse. Actually this is a defense of religion as a framework for defining belief.
I’m arguing that secularism when taken on face value lacks the tools to recognize it’s own belief system.
I know trivial beliefs e.g. today was 85º – we can agree that calling those religious would not be useful.
Using your original logic, -any- belief can be religious in nature. “Today was 85” -is- religious from your original position because perhaps people ritualistically check the weather every morning like a prayer. The weathermen are like priests disseminating knowledge, and small talk is used to find other weather checker cultists.
It does not matter what belief Id offer up, because it will match your original definition because your original definition is so broad as to be meaningless. Other comments have already said this in fewer words. If you are unable to identify what it would look like if you were mistaken, then you shouldn’t be confident that you are correct. So how could someone identify the difference between a secular belief and a religious belief?
Truly a bonkers assertion when secularism includes enormous institutions to fund and perform tasks as various as the hard sciences to the most abstract philosophical investigations and the entire gamut of cultural production around and between.
The average person doesn't much participate in these institutions but the average Catholic hasn't read Humanea Vitae either.
People are often not secularist because they don't reflect, usually they have specific reasons that they are aware of and that they might question in the future.