In a way, I think it's a bit unfair to criticize Nintendo for porting Wii U games to the Switch. Nobody had a problem with HD versions of Zelda games coming to Wii U from previous systems. The Switch ports of Wii U games are similar. The resolution & frame rates have been boosted and there are small additions here & there.
As for the cost, Nintendo games usually command high retail prices unless they release a greatest hits version.
I also think that it's a smart move to port these titles. Let's face it - the Wii U was a retail failure. Many of these great games didnt reach a wide audience. If you weren't a Nintendo diehard, chances are you never got to play these games. Should they be forgotten? Left to rot on a system who's unfortunate name & confusing marketing meant they were generally overlooked? I dont think so. They are better than 90% of the 3rd party, microtransaction-riddled deck getting churned out these days.
As for the library being mostly Wii U ports, I have to respectfully disagree. 1-2 Switch, Arms, Fire Emblem Warriors, Kirby Star Allies, Legend of Zelda Breath of the Wild (simultaneous release), Mario & Rabbids, Mario Tennis Aces, Nintendo Labo stuff, Octopath Traveler, Pokemon Let's Go Evee & Let's Go Pikachu, Snipperclips Plus, Splatoon 2, Starlink, Super Mario Odyssey, Super Mario Party, Super Smash Bros Ultimate, Travis Strikes Again, Xenoblade Chronicles 2 & Torna the Golden Country are all new, Switch exclusives. Yoshi, Metroid Prime 4, Pokemon, Bayonetta 3, Fire Emblem three Houses, Luigi's Mansion 3, Town and Animal Crossing are all announced upcoming exclusives.
Those are all Switch-exclusive, compared to ports of DK Tropical Freeze, New Super Mario U Deluxe, Captain Toad, Bayonetta 2, Pokken Tournament, Hyrule Warriors and Mario Kart 8. Big difference and ALL of these ports are great games that DESERVE a second chance on a system that is selling 10 times better than their original, overlooked home.
PS: For those counting, It breaks down like this for Switch Nintendo-published exclusives.
New Releases: 28 including announced, unreleased titles
Ports: 7, 8 if you want to count Zelda's simultaneous release