That Corbyn fella...

We weren't talking about the 'McCarthy era', and I can't remember seeing it referenced recently. We were talking about what 'McCarthyism' has come to mean. A further quote from further down in the same article:

Since the time of McCarthy, the word McCarthyism has entered American speech as a general term for a variety of practices: aggressively questioning a person's patriotism, making poorly supported accusations, using accusations of disloyalty to pressure a person to adhere to conformist politics or to discredit an opponent, subverting civil and political rights in the name of national security, and the use of demagoguery are all often referred to as McCarthyism. McCarthyism can also be synonymous with the term witch-hunt, both referring to mass hysteria and moral panic.

All of these things have recently been tried on Corbyn, which is why the reference is accurate, pertinent, and justified. It's not a question of how it 'would feel' to Corbyn, either, but what his political opponents clearly aim to achieve by smearing him in this way.