A lot of science bloggers call themselves "skeptics", and are always on the warpath against religion (like Christianity) and pseudoscience (like homeopathy). I am more concerned with bad thinking that corrupts otherwise-intelligent scholars. Here are my main targets.
Paradigm shifters - They subscribe to T.S. Kuhn's theory that science is all a big popularity contest, with new theories winning out without any rational or measurable advantages, and never making progress towards truth.
Proof deniers - They fail to appreciate that a mathematical proof can give certain knowledge.
Goedel fools - They argue that math lacks solid foundations because of some technical logic theorems.
Einstein idolizers - They treat Einstein as a god, and learn all the wrong lessons from the history of relativity and the Bohr debates.
Thought experimenters - They endlessly speculate about a black hole interior, or universes before the big bang, or quantum gravity, or other questions outside the domain of observable science.
Falsifiers - They deny that science teaches us anything, except that older theories have been
Dreamers of imaginary worlds - They like to invent fantasy worlds, and put them out under names like the multiverse, many worlds interpretation, and strings in higher dimensions.
Hidden variable searchers - These are always telling us that quantum mechanics is incompatible with realism because it fails to identify the hidden variables that will unlock all the mysteries of the universe.
Publicity panderers - They will say whatever gets media attention, such as fantastic claims for quantum communication and computers.
Political correctness enforcers - On an assortment of topics (global warming, evolution, human biodiversity, etc), they are more interested in silencing their enemies than promoting scientific truth.