IARC originally classified coffee as a 2B carcinogen, "possibly carcinogenic", in 1991. This was the same classification as for magnetic fields (more on the IARC classification scheme). Some people cite this to try to put the risk from magnetic fields in what they see as the right context - magnetic fields are classed the same as coffee and we all still drink coffee.
The IARC web site actually says:
"Coffee is possibly carcinogenic to the human urinary bladder (Group 2B).
NB: There is some evidence of an inverse relationship between coffee drinking and cancer of the large bowel; coffee drinking could not be classified as to its carcinogenicity to other organs."
So the picture on coffee is mixed - possibly causes one specific cancer, possibly protects against another, not enough evidence to tell for other cancers.
We think this was actually a good illustration of something different. When deciding what action to take about a possible health hazard, you have to weigh up lots of factors - including how big the risk is and what benefits the agent brings. WHO among others says something similar when considering precautionary action for EMFs - the action chosen has to be proportionate.
Then, in 2016, IARC re-examined the evidence and lowered the classification from 2B - possibly carcinogenic - to 3 - insufficient evidence. So coffee is no longer classified the same as magnetic fields anyway!