Sorry to see this kind of misinformation about why the Seattle City Council acted. Taxi drivers pay commercial driver's insurance ($7000-$11000/yr) that insures the city against third party personal injury and property damage claims due to taxi accidents.
Ride-sharing companies offer cheaper fares because they don't pay for the same level of insurance, shifting the burden of liability on to riders, tax payers and the general public.
Protectionist laws aren't automatically good because they have some questionably-beneficial aspect. And in this case, they aren't protecting anybody involved, just the city. Are you kidding?