That’s not what an average home cook can do regarding knife skills. These services and recipes should be written for their audiences which are likely typical home chefs that don’t handle knifes that well. I’ve been cooking 40 years and have certainly tried to use a knife that way and it always feels unsafe to me. Also, typically requires a very sharp set of knifes which I do keep but I don’t think the average house does.
It's not what an average professional cook can do either but it's still one useful reference on how long it takes to chop garlic. No one is going to follow a pasta recipe that says it takes three hours because they do shit like allocate 4 minutes per clove of garlic.
They should estimate based on a average user. Or at least give more context than a single X minutes. Three hours is a bit excessive as an example but the difference between 20 and 45 minutes is crucial and more representative of common underestimation. They could also suggest things like buying Preminced garlic to eliminate common timely tasks. Instead they tend to go the other way and would be more likely to recommend you go foraging for wild garlic
