Not to prolong the agony, I tried the example on OSX for man tbl:
.TS
tab(@);
ccc.
This@is@centered
Well,@this@also
.TE
It didn't work with the nroff -man they supply. It did work with mandoc
So my summary of understanding so far:
FreeBSD: does not honour .fc no longer has functional tbl or nroff in base, does have mandoc which honours .TS/.TE
OSX: does not honour .fc, no longer has functional tbl, nroff is braindead, does have mandoc which honours .TS/TE
debian: has nroff and tbl. nroff appears to be groff. honours .fc. The minimal install does not have mandoc. apt install mandoc and it works.