I think it depends on your situation.

Is your job stable enough where you could easily pay off the mortgage every month? 

Does your income fluctuate a lot?

If you lost your job, could you still pay off the mortgage every single month without having to worry about it?

Does having a mortgage make you lose sleep? 

Also, if you are posting about it, it is likely taking up mental real estate in your head that can be used for other productive things.

Often times when I see people post things like this they are super proud and think a lot about it too much about it.

Something I started doing recently, was not thinking about credit card points. It was taking up mental real estate in my head and it wasn’t productive. I already know I’m getting a rebate for it. Why am I thinking about it and justifying it so much?

It’s pointless and a waste of time.

I just buy what I need and then when my bank notifies me I have X points I’m like “cool I’ll invest more now”.

People who brag about having a low rate on their mortgage, treat it the same exact same way.

And if you’re posting about it, you’re simply doing it for clicks. Why? because you already know it makes mathematical sense to not pay it off because you’re clearly an investment page.