Any language* has different registers. What is unremarkable in one may jar in another. When Ms Chalabi invokes the OED in support of the use of the word ‘literally’ to mean ‘figuratively’, she skates over the fact that it has the qualification ‘informal’ next to the definition.
If you want to maximise your chances of being taken seriously in a given context, you should use the register appropriate to that context. Anyone using ‘literally’ to mean anything other than ‘literally’ in a piece of formal written English is undermining those chances. Conversely, anyone using excessively formal language in a web forum risks being regarded as a pompous idiot. Double for people who criticise others for not using such language in that context.
And ‘less’ for ‘fewer’ is perfectly standard in formal Scottish English.
* I’m expecting someone with more knowledge than me to list those languages where this isn’t true.
