The Church allows passive attendance at non-Catholic services if civic duty compels us to.
this is debateable..what about this
Pope Pius XI,
Mortalium Animos
(# 10), Jan. 6, 1928: “...
this Apostolic See has never allowed its subjects to take part in
the assemblies of non-Catholics...”
2
What about it? Catholics are not allowed to take part in non-Catholic services.. They are allowed to conditionally and passively attend.
what's the difference in your mind between
assist actively
or
to have a part in the sacred rites
what would consist precisely of" have a part in sacred rites?"
Attend but don't drink the grape juice. 
Passive attendance of a major life event death, marriage should be fine, but with limitations, especially on the marriage part.
Canon 1258.1, 1917 Code of Canon Law: “It is
not licit for the faithful by any manner to
assist actively or to have a part in the sacred rites of non-Catholics.
passive attendance to a Jєωιѕн funeral is fine with you? Jєωιѕн marriage is fine with you?
the jew, greek orthodox , novus order marriage or funeral are all fine with you or do you make distictions between them?
I'm not sure what the canon really means by "to have a part"