As boiled down as I can think of: LRFD (in a sense) puts more emphasis on the 'uncertainty' of the applied loads, and more trust in the strength of materials and quality of workmanship, etc (as we would like to imagine in modern construction). ASD generally says that we know, more or less, what the applied loads are going to be, and discounts the strength of materials and quality of workmanship. For example, LRFD puts more 'safety factor' on live loads than it does for dead loads. This is generally applicable when designing buildings as there are both dead and live loads. When designing a lifting lug or something, there is pretty much just 'a load' being applied. So the LRFD load factors are not quite applicable to such a system as they would be in a larger structure - "is my lifting lug carrying a live load or a dead load", vs. "I have this load I need to support, lets take some capacity off the material side of this (i.e., safety factor). Hopefully that gives a better idea of why LRFD might not be appropriate for that type of component based design.