You missed the point; we all have to agree on dates to communicate so you should get your facts straight.
You said that:
That being the case, we as a culture have also decided that decades start a year x0, centuries start at x00, and millenniums start at x000.
This is factually incorrect as centuries END in that format. The last year in x00 is the end of that century, not the beginning.
Then you state:
Beyond your lack of education on how the language you are using works, you seem to think that there is something concrete about what dates are what. As stated earlier, our dates are simply an arbitrary way for a bunch of people to agree on time.
This is incorrect in itself because it claims
A: setting dates is an arbitrary way for a bunch of people to agree on time, against the claim B: that there is not "something concrete about what dates are what". I would ask you to point to your sources for that claim and find an example of people not using their calendar and matching it with different calendars from other cultures and having them all match up to form a cohesive timeline with whatever reference each culture has set. This is accepted as standard and there is no arbitrary old or new method of referring to dates just what calendar you choose to reference. Please show authoritative examples if you disagree. Just because uneducated people think something doesn't mean that they change scientific fact or change the accepted method of referencing or calculating things by people in the field who have the education to make claims about the proper way to do something in that field.
To address your original claim: please reference this site to understand the year 1 issue:
If you have another viewpoint please cite examples.
You don't want to be, as you say:
a pseudo-intellectual halfway thinking through a subject, making a mistake, thinking they have found an "ah-ha" idea, and then refusing to re-evaluate when it is pointed out that they are wrong.