No one is saying that whatsoever. Obito in base form with 1 MS has effortlessly dodged attacks comparable, and faster than Minato's striking speed, which is not instantaneous, like FTG.
To reiterate, FTG transport speed =/= minato's striking speed.
Let me put it another way, no matter how fast Minato can teleport to a location, his reflexes and striking speed are all that needs to be dodged. Do you finally get it?
If striking were instantaneous while using FTG, Madara would have been hit easily, but because Minato's reflexes and striking speed were not enough, Madara countered it despite the instantaneous travel.
Yes, it is an inconsistency. I think he knows his own limits, and that's why it was never used in life or in another battle. He was clearly out of options and desperate.
Despite using it for all of 5 seconds, he was still swatted away, while (admittedly a rikudou chakra enhanced) 1 MS Obito was able to dodge that same striking speed. Take away the SM and the Rikudou chakra, and the speeds would be decreased in the same amount, still leaving MS Obito's Kamuiing speed as faster than Minato's reflexes. (And that's giving Minato the edge, as SM directly increases one's reaction time, while Rikudou chakra does not.)