I’m not quite sure why i’m responding here.
It’s absolutely astounding how ignorant people are to basic tumah v’tahara issues.
1- as said before Tumah goes up to the Raki’ah (why some people think it stops at the clouds , not quite sure
2- the idea that it cant have a hole is false. 2a- Mukaf Tzamid Pesil can have holes, it’s a common misconception that it cant
2b – thats not even (IMHO) the issue here
3- the issue as discussed in MANY mishnayot in Ohalot is that something which is not mekabl tumah is Chotzetz befnei Hatumah
A hole if smaller then a tefach will not transmit tumah into the bag
4-plastic since it was not around at the time of the gemara is a mechloket achronim (similar to the tevilat kelim issue) if it’s mekabel tumah. the Kohanim that are prepared get something that is made out of something that definitly isn;t mekabel tumah
regardless i’m assuming he relies on a sfek sfeka for the plastic