My AP history teacher liked to make up stuff. But like, he’d say he made it up right after telling the made-up thing.
TIL I’m your AP history teacher (just kidding, but I do enjoy recreationally lying to children)
Was your brother my 6th grade history+english teacher who spent more of class time having recess or playing Risk (the board game) than anything else?
But if you read a primary source, that’s one persom who had the opportunity to make stuff up. With a secondary source, even if the primary it’s based on is legit, there’s some other guy who wasn’t there and may either be lying to you or misinterpreting the primary source his report is based on. Each new level of isolation adds another opportunity to stack both lies and mistakes onto the data.
It’s not that you can’t go wrong with primary sources. It’s that you can go a lot wronger without them.
Counterargument, secondary sources are often a good filter for bogus primary sources. This is the primary reason Wikipedia does not allow primary source references.