I can understand separating it out based on what type of contractor they are but not a general independent contractor.
For one companies can and do purposefully put employees on 1099 independent contractors to avoid paying benefits depending on the company
For two some of these are just like other services one uses that it is customary to tip.
Uber/Lyft act like taxi's. Yes regulatory-wise they don't often want that but the services they provide are just like a taxi. And any other ground transportation service, you normally tip there so I would expect to tip Uber or Lyft.
For food delivery it's customary to tip as well. Plenty of times we order from a restaurant directly but they contract the delivery out to DoorDash. Well you'd tip the delivery person normally so you end up tipping an independent contractor.
But your appliance repair guy who does his own thing? Sure that's different. Honestly I'm not certain how the services the PP mentioned in the comment you quoted relates to your dad and him being insulted on top of his job rate. I can only assume you're talking about someone like a repair person who has a set rate for their labor. That's not at all related to Uber/Lyft or deliver for Uber eats, Doordash, Instacart because that's not how those occupations work.