Yes, all claims to be "objective" fall to ultimate subjectivity.
- Every observation, is a subjective observation
- every threshold of relevance, is a judgment choice
- every conclusion, is a judgment call about how to evaluate a claim
But "subjective" is mis-treated as a dirty word
All of science, all empiricism, is based on intersubjective consensus of experts.
We know how to create instruments to detect a phenomenon, because the experts in the instruments, and in the phenomena, have reviewed phenomena and the instruments response, and consider the instruments the best way to characterize the phenomena.
We know valid and invalid says to do statistical analysis, because statistics experts have evaluated different methodologies and concluded certain practices give useful methods of discriminating.
We know how to set up experimental protocols (things like double blind with controls, experimental setups like corner box, etc) based on experts having tried a variety of techniques, evaluated their effectiveness, and FOR THAT TYPE OF PROBLEM, recommending a protocol.
For different problems, the experts that one is trying to reach consensus among, vary. For anthropogenic global warming, it is a small group of cross-discipline experts who have been studying this particular problem. For how to fletch an arrow, it would be a small group of craftspeople who are maintaining that skill. For whether a defendant is guilty, it is a small pool of jurors who have considered all the evidence. For who should be our next president, it is all adults of voting age.
So "sufficient evidence", while intersubjective rather than objective, is far from worthless as a criterion for belief.
Note, I too have encountered many who claim to only operate on verified scientific conclusions. In addition to questioning the objectivity of any of this, I also dispute whether any such a claimant actually meets their own standard. I offer the following methodology pursue this question, look at the decisions they made in the first 10 minutes of their day.
If one starts the day upon waking -- what was the sufficient evidence of where they were, of what the feeling in their guts actually meant (full bladder, most likely), of the safety of transferring their weight from bed to floor (floor not a visual illusion, say), etc.? Go thru 10 minutes of their morning, and 99% of what they do will be based upon first person observations and judgments, unverified memories, and prior successful routine -- virtually none of it will be even intersubjectively verified, much less scientifically verified.