You've criticized, among other things, the assumption of uniformity that underlies such things as radiometric dating. And yet different methods of dating have been shown to produce consistent results, and scientists working with the assumption of uniformity have been able to make predictions that bore fruit.
Are you aware of the procedure for procuring these dates? The lab typically asks the client what age he or she expects the sample to show. The lab then will do 30, 40, 50, or 60 tests until they get the desired number. The sad fact is that closed systems probably do not exist in nature (things leak in and out all the time), yet a closed system is the only environment that could facilitate an accurate measurement. In summary, radiometric dating is simply a guess that has as its starting point what the investigator thinks should be the age...
Do you have a source for that? I can imagine a lab doing multiple tests to see if they converge on a consistent answer, but you're implying that they'll simply discard 50 tests that don't give the expected answer in favor of one that does. I'd like to see some support for that charge.
As for the expected age issue, here a self-described conservative Christian scientist explains why labs ask how old the client expects the rock to be. It's not as insidious as you think. (Scroll down to the first blue answer.)