Nobodies saying it is, in this particular cas cross polleniation isnt an issue either as i dont think weeds resistant to potato blight would be that big a deal.
TBH most crops are nearly as bad, poppies in particular are terrible for getting everywhere, as is rape. but neither are as bad as naturally occuring weeds (you every tried to get rid of that vineweed stuff? its like a bloody triffid. mushrooms too are terrible)