I don’t think they’re confused by the “100W equivalent” part. They’re asking about the limits marked on the switch. The reason it lists both is that the dimmer is genuinely rated for a smaller LED load than it’s rated for an incandescent load. But then they also looked it up and found the rough formula for calculating that derating yourself (in the event it’s an older switch or whatever that hasn’t already done the LED math for you) and got confused.