The equivalent to 1.5% is 7.7% - not 5%. So if they got 7.7% they would be making exactly the same as they would have if they got annual raises. Making up for the $2,128.38 differential requires that you set a period in the future where this different should be made up. Let's say 5 years works out to $425/year or an additional 2% which brings the raise up to 9.7%. $15 is a 30% increase which vastly outstrips anything that would be justified based on 'catching up to inflation'.
So how long till the next raise? That's the problem with not indexing the minimum wage and doing things ad hock, you keep having these debates.
As for what people "deserve" to be paid. We live in a free market society where prices are set by supply and demand. The only time people don't
"deserve" what they are paid is when the government interferes. They tried to create society where everyone got paid what they "deserved" in the USSR. It is not work out so well.
A minimum wage is not Marxism, a maximum wage might be. So you do think people on minimum wage are over paid.