Don't worry--that is not true at all! The only time something like that could happen is if a breeder were to breed selectively for traits by inbreeding and things like that, which pass on weaker genes to the offspring. That can happen with any budgies, though, if they are bred irresponsibly.
Recessive pied budgies are not at any higher risk or illness or disease because of their genetic mutation
Yes- it is true that the recessive gene has several faults in the gene pool. It is true that You should never breed two visually ino birds together as the chicks will be weaker, smaller and have even more sensitive eyes. The recessive gene pool also carries the traits for defects such as a weaker immune system, smaller size and shorter lifespan. That is why if you wish to produce healthy birds of the recessive gene, you breed a dominant **** to a recessive hen, a recessive **** to a dominant-recessive hen or a dominant **** split recessive and a dominant hen. Breeding two recessive gene birds together certainly has its affects on the birds and is easily seen in the show ring, the birds will be of better colour but the overall health is compromised. recessive to recessive mating's are not accepted in the show scene.
This can be compared to dogs in a way- NEVER should you ever breed two Merle dogs together- this produces the double or 'white' merle and the dogs have severe health issues.