“I’m just saying”

This is a phrase I've often seen in comment sections of blogs and videos. Those comment sections frequently degenerate into hothouses of abuse, in which a poster is likely to receive a venomous reply. I imagine that by concluding a comment with "I'm just saying" anticipates such a response and attempts to allay it. Which is to say, the phrase may be used to try to soften remarks that might be construed as criticism.

In 1826 it occurs in print here:
Hearings Before Subcommittee No. 3 of TheCommittee on the Judiciary, House of Representatives, Eighty-first Congress,

as "I'm just saying that this is ridiculous and unfair".

As a stand-alone sentence, possibly about 1936.