It also damages their credibility when they cross the line from "here are the epidemiological facts" to "here are the appropriate tradeoffs between economic stability and acute illness prevention". The latter is not a question that an epidemiologist is any more qualified to speak to than anyone else. Those are political decisions.
They do the same for global warming. The nature and extent of anthropogenic climate change is a question for scientists. But they have all also latched onto the conclusion that global wealth redistribution is the only solution. Again, they are laundering their scientific expertise into political authority. I more or less think that the scientific process moves us to toward better understanding, but the collective political opinions of scientists should not be mistaken for science.
When the experts are abusing their status to pursue political ends, then it's no surprise that the people they seek to politically vanquish put up a resistance by attacking that expertise.