From what I've read its only expected to be positive on anti-body tests, not on tests for the virus which are supposed to be very rarely positive after vaccination.
So if the tests given in the nursing home were anti-body tests, no big deal. Otherwise it would seem the vaccines are not working as expected.
Not sure I agree with you. Not an expert just trying to keep up. But they never said the vaccines would prevent infection or spread. They just said it would reduce risk of severe illness.
Which in and of itself, barring all other questions and concerns, would be a good thing.
But IMO we should fully expect positive tests to rise even among the vaccinated. If the Delta variant is as transmissible and potent as they say, then expect it to spread even among the vaccinated. Ideally, no big deal. I am of two minds. The vaccinated should, in theory, have reduced risk of severe infection. So should the previously infected. On the other hand, viruses that kill their hosts die with them. So Delta may be more transmissible but is it more deadly?