Cog merely displays his ignorance with his 'Dirty Hippie' myth. Long hair and beards does not equate to uncleanliness.
Like all young people, they actually bathed more often than the older folks, and focused on their generations style of grooming, perhaps unrecognizable by fuds like Cog. After all, as with all younger generations, the focus was on the opposite sex.
The older generation still referred to the 'Saturday night bath', while the younger generation bathed every day, just like people of that age in every generation.
Any pictures of people with long hair who actually were dirty were exceptions not the rule, and were often used in establishment propaganda; i.e. 'dirty, scary biker types' or 'near-death needle junkies'. As with today, using fear in an attempt to sway the masses.
A song of Cog's kind at the time,
https://www.youtube.com/watch?v=-iYY2FQHFwE"A place where even squares can have a ball"
"For my part, whatever anguish of spirit it may cost, I am willing to know the whole truth; to know the worst and provide for it." - Patrick Henry
The level of injustice and wrong you endure is directly determined by how much you quietly submit to. Even to the point of extinction.