My own recollection differs only slightly. I do not recall Hubert being in the same league as present day Democrats. But that had changed by 1972, with McGovern.
As for Johnson, Kennedy, Stevenson, and Truman:
In my memory they all were pro-American, a HUGE difference from the Democrats of today. Kennedy and Truman in particular were pro-American. Stevenson was a Democrat senator from (what was then but no longer) a Republican state. Johnson was something of a blowhard but I would not accuse him of being anti-American.
As for FDR, I was born during his administration so too young really to have a first hand opinion. FDR certainly had socialist tendencies. However, I would never accuse him of being anti-American.
Bottom line, the hate-America Democrats of today are most assuredly a bright line break with their predecessors. Americans living during the times of the aforementioned Democrat candidates would not have given today’s crop of despicable Democrats the time of day. They were far too smart for that.