The answer is somewhere inbetween.
Polysporin can lift ink (as can any other anitbacterial or antiseptic cream).
That said it will only lift ink if used in too much abundance.
The reason that tattoo artists suggest this stuff also A&D and Savlon etc for teh first couple of days is because you have an open wound on your arm.
Until that tattoo scabs over/seals shut you are highly open to infection. That is why it is suggested that a sterile-non stick dressing is applied for the first 12-24 hrs.
The best way to use polysporin etc is with extreme care.
For the first 2-3 days apply a small amount just enough to cover the surface area. Do not slather on half a bottle/tub. You need only apply it once in morning and once at night.
This keeps the bacteria out of the cuts and when the scabs form you can swap to a moisturiser of choice such as tattoo goo or aquaphor, (or whatever non-scented lotion you prefer).
If you swamp your tattoo in antiseptic cream after it has scabbed then it will lift ink. This breaks down the scab which contains the pigment that is being held in developing scar tissue.
Hope that helps you decide whether to use it or not.
The only difference between a person with tattoos, and a person without is this. The person with tattoos does not care if you do not have any.