To a scientist, junk science is badly done research, usually with the aim of supporting a social, political, financial, or religious agenda. The classic junk science was the 'data' showing that vaccination causes autism, or that smoking does not cause cancer. A lot of social 'science' is junk because the methods are designed to support a (usually left-leaning) political agenda.
To the public, junk science is an accusation hurled at solid scientific research which suggests that we should change old habits for the good of other people or the environment. Rush Limbaugh is not the most qualified judge of scientific merit or integrity. The science behind birds and ingested lead has been solid for 50 years. Calling it junk because there are still vultures in the sky is just saying that you want to continue using lead because you don't like the alternatives.
I don't like them either, but I do like condors and am willing to use copper bullets to help them recover from the brink of extinction. I must be a junk scientist.
