I assume the implication here is that the thing they said 10 years ago was less inappropriate back then. So how do you predict sensitivity changes 10 years in the future to limit your speech today? Even if you delete posts after, say 1 year, archives exist. Shouldn’t you just not say anything if you’re afraid of this? Maybe discussion of self-censorship like this will be taboo in 10 years and the ship has already sailed.
My thought was more about time and distance. Something can be unpopular or even wrong when it's first said too. People are dynamic and change over time. The mechanism of change is living their lives.
Taboos can change as well, so there is a motivation to steer clear of controversial topics in recorded media. You can use discretion to judge risk. It's unlikely that someone's going to fire you for discussing ice cream in 10 years.
There is no way to know what people are going to get offended about in the future, but the clear trend is people getting offended about more and more things over time, rather than fewer and fewer things.