What he said was (AFAICT, the exact "we don't break userland, period" wording only appears in this HN thread. Let's go with the rant that I believe the GP was referencing):

The "first rule of kernel maintenance":

    If a change results in user programs breaking, it's a bug in the
    kernel. We never EVER blame the user programs.

Then later, to drive home the point:

    WE DO NOT BREAK USERSPACE!

So, sure, "there was no asterix on his statement saying to read the fine print"--he did better than an asterisk and fine print, he made it part of the main content.