While I understand what you're saying, it's cultural and personal bias, and it's present in everyone and everything. Experts are experts, and they are able to sort through
field of specialty better, stronger, and faster than non-experts. But, they still all carry their own biases. That's what the original poster was about, I believe.
Looking at historical works about prior historical works can absolutely teach you about the source event. But it is also an incredibly relevant and accurate way to learn about cultural norms and the society the piece was created in.
Most experts go their entire career just trying to identify their own biases and eliminate them from their scholarship; it's harder than it looks because they're so ingrained into our personality.
In theory, the perfect expert follows the evidence to the appropriate conclusion. Only in theory.
In execution, they follow only specific lines of reasoning, certain thought patterns, and certain investigation patterns because of the cultural expectations and social mores the expert has developed, was trained under, and has lived with their entire lives.
edit; OP also said nothing about baseless claims. Just that the scholarship we read will be relevant in the future as a snapshot into our lives, as well as whatever the research is about.