That is not what i wrote! I told you the way you show it to be used is useless. I gave you an explanation on how to use it such that it makes sense. And part of that is explained with the sentence you do not understand.
For more detail: I gave an alternative way that does not rely on power flags at all. (Some people simply prefer it that way) For this one creates custom symbols for every component involved in the supply chain. (These custom symbols then have the pins involved in the supply chain set to power output where necessary)
The sentence you quote is there because it is not really sensible to make a special fuse or resistor component with one pin set to power output. (What happens for example if you copy that resistor symbol and place it where no power supply line is? This could again be something that hides a true error or it could if you are lucky generate a false positive ERC error.)
Because of these downsides i feel that it makes more sense to use the power flag for such cases. (And by extension maybe even for things like connectors if you are not prepared to fully redesign the graphics of it to clearly communicate that power comes via this connector.)
An alternative explanation can be found in the FAQ: ErrType(3): Pin connected to some others pins but no pin to drive it
If you do not care for an additional check against the common mistake of forgetting to supply components then use the power flag as shown in your picture. Simply place it where ERC complains and be happy that it stops complaining. This will however not help with finding true errors in your schematic as it simply hides the symptoms of it. (Like taking a painkiller for a broken leg without fixing the leg itself. Yes there is no pain anymore but the leg is still broken.)