The glue will probably be the strongest part of it, but finger-jointed hardwood isn't that terrible. Any decent wood glue is crazy strong.
The problem with knots is that they resist drilling and screwing. The problem with new growth is that the pith is the weakest part of the wood, and new growth has the most pith.
Still, it's not a weak and terrible pos wood-like material like 1990's MDF, it will probably be ok for most uses as long as the grain direction is respected in regards to shear direction (typically you want the grain direction to run perpendicular to the shear forces) and everything is properly braced.
The piece in question involved one of the starting wood sections being finger jointed with the grain running along the joint line. It failed where the bases of the fingers were tangent to the grain, which seemed pretty predictable to me just looking at the wood.
The problem with knots is that they resist drilling and screwing. The problem with new growth is that the pith is the weakest part of the wood, and new growth has the most pith.
Still, it's not a weak and terrible pos wood-like material like 1990's MDF, it will probably be ok for most uses as long as the grain direction is respected in regards to shear direction (typically you want the grain direction to run perpendicular to the shear forces) and everything is properly braced.