We say Witnesses got all excited over something that turned out to be a big nothingburger. Give them the short answer - ‘Everyone is allowed one failed end-of-world date per lifetime. It is in the rules’ - and be done with it.
Valid observation for me. When first encountering the idea about 1972, I thought it was everyone's understanding as I knew very few Witnesses. But as time went on, I found it to be a patchy eccentricity rather than hysteria.
However the fact remains that some of Jehovah's Witnesses DID get seduced by the song of '75 and some of Jehovah's Witnesses DID NOT get seduced by the song of '75.
And yet, we're all still here! GET OVER IT!