There are 2 things to keep in mind there.
1.) Where did Bardock go (or more when) and
2.) The canonity of the films.
Where did Bardock go or more when:
When Freezer hit Bardock with his attack he was displaced in time a thousand years into the past. And single handedly disposed of a member of freezers species by turning super saiyan. Chilled though survived the encounter at least long enough to speak out a warning about a super saiyan.
So there is no real inconsistency if we take this into account. Saiyan myth says 1000 years ago a super saiyan appeared and Freezer fears this LEGEND. Bardock was a super saiyan 1000 years ago and put fear into chilled about a super saiyan.
So in total: No inconsistency there, aside from the flashback in the series where the super saiyan is shown as someone in a more ape like form than a normal humanoid.
Canonity:
The films are almost never considered to be part of the main canon and thus are often ignored in the series. For example the Broly films....no info from them ever show up in any of the series aside from super now using a broly like transformation for an universe 6 Saiyan.
Exceptions exist of course like 2 films being integrated (and remade) in dragonball super, but before that the events inside were largely ignored by the main series (and often raised a few questions about abilities,... if they would have not been ignored).
