One problem is the American League in 1901 was essentially a minor league that decided to challenge the National League as a major league. They signed a few NL players and moved franchises to large cities. Lajoie was a talented hitter in a league that still had many “not major league players”.
My point is that there is no line. 1901 is certainly not substantially less modern than 1898, or less modern than 1906. Drawing the line at 1960 would certainly be a strange decision; I see even less logic behind saying that 1958 is less relevant than 1963.
Technically, someone hitting .426 in 1901 has no “relevance” to any season other than 1901, after all. It didn’t help anyone win in 1902.
Stating something is a record is just a matter of statistical fact. It is indisputably true the level of baseball played then was not remotely close to today, but then I honestly feel the baseball being played in 1975 was quite inferior to today, but the 1975 season still “counts.”