I looked at the Schedule E instructions for 2012.  The same language was probably there 20 years ago also, but you should have noticed it in the last decade:

Activities That Are Not Passive
Activities

Activities of real estate professionals.
If you were a real estate professional for
2012, any rental real estate activity in
which you materially participated is not
a passive activity. You were a real estate
professional for the year only if you met
both of the following conditions.
• More than half of the personal
services you performed in trades or businesses during the year were performed
in real property trades or businesses in
which you materially participated.
• You performed more than 750
hours of services during the year in real
property trades or businesses in which
you materially participated.
If you are married filing jointly, either you or your spouse must meet both
of the above conditions without taking
into account services performed by the
other spouse.

https://www.irs.gov/pub/irs-prior/i1040se--2012.pdf