Even when it descends into personal insults?
I find it hard to believe that describing someone as having “a Mr Spock hairdo and owl eyes” is acceptable in any situation.
One can put arguments forward in an opinion piece quite legitimately and forcefully without resorting to personal insults.
That quote was just unnecessary.
For context, this wasn't an opinion piece, it was the political sketch - a sort of cartoon in written form. In the preceding couple of days alone, the Times sketch also referred to Alan Sugar as a "stubby-fingered megalomaniac", to Chuka Umunna a "scion of the Anglo-Irish-Nigerian gentry [who] radiates the most tremendous levels of to-the-manner-born poise", and to Boris Johnson as "a crouched, squat, albino-ish conductor waving his hands in an effort to stir the orchestra".
I'm not defending the practice - I think it is well past its sell-by date - but this is not, as some people seem to be taking it, a random insult apropos of nothing in an otherwise straightforward opinion piece.