Well, not everything that appears important really matters most of the time; it might matter to some, and to some it might not add any value, and celebrating just a dominance registered date won't add anything to the bearish market that we are about to face in the bitcoin market, or will I say that we are already on?

It's obvious the guy who made that tweet is just looking for a way to get noticed, as it was clear with his statement, as he probably dumped some bitcoin in order to get noticed.
Either way, it's good that there are historical records that are well kept and will be remembered someday, even if they're not celebrated as expected. We individually add value and meaning to whatever we want, so that shouldn't be a problem. You can also celebrate it from your end if you want.