Simple, if no dating methods correlated then that would be evidence that past "constants" were not the same as present "constants". There's no reason that any dating methods would correlate if they were all sent out of whack as things changed. Where are the inconsistencies?
Since you seem to be claiming that there was a discontinuity (rather than a gradual change), then it reasonable to think that you concede that current dating methods give accurate results back to the point of that inconsistency. But following that logic, there should be a point where all dating methods suddenly stop correlating, since things before that point do not happen in the same way as they do after that point. Can you show evidence of this? If you can then you've falsified the assumption that things in the past worked in the same way that they do now!
But if you can't provide any evidence of this discontinuity then what you're claiming is nothing more than a blind assertion, and that makes you a pretty big hypocrite (since you seem to be deriding people you claim are making blind assertions/assumptions). We have evidence of how things work now, we have no evidence they worked differently in the past, therefore the only logical conclusion (based on current evidence) is that they did not work differently in the past.
Now if you were simply stating that things *may* have worked differently in the past then I could live with that, but you're not doing that. You're claiming that they definitely did work differently, when they changed to how they work now, and all this with no evidence whatsoever. Now everyone else is making an inference based on evidence (physical evidence of the universe, which is what we're all hypothesising about). You're making bald assertions based on nothing. Need I say more?