The age of the Universe from a large sample of the oldest Galactic stars

> Our inferred A⋆ is consistent with the 13.6 Gyr expected in CMB-calibrated ΛCDM, assuming the first long-lived stars formed when the Universe was 0.2 Gyr old. This agreement casts doubt on solutions to the Hubble tension solely through new physics prior to recombination, which generally imply a cosmic age of 12.9±0.2 Gyr to match low redshift probes. It is difficult for stellar modelling uncertainties to reconcile such a low age with our result given the low metallicities of the oldest stars in our sample and independent asteroseismic constraints.

So the expected age of the universe hasn't changed, but some alternatives to ΛCDM look less likely.

Can someone explain this sentence from the intro?

> To remove stars with unusually high and precise ages, we require old stars to be metal-poor and α-enriched.

Particularly, why remove stars "with unusually ... precise ages"? Why does increased precision decrease plausibility/accuracy?

And yet again the age of the universe is pushed higher. As our understanding improves, it tends to get older (and larger).