I think I made my point unclear by the last line. Of course, extraordinary events don't mean once in a lifetime occurrences. Also, not all freak accidents are considered extraordinary.

Several cases for EC261 have been tried in EU Courts and those cases do note that ...

"The extraordinary event is not inherent in the normal exercise of the activity of the air carrier and is beyond the actual control of that carrier on account of its nature or origin."

So say, an airline operates out of EU airport A where there are remote stands. The plane wing is struck by the mobile stairs causing a technical delay to check for damage. This is a "freak accident"; but is not considered extraordinary since operating mobile stairs near and around an aircraft would be part of the normal exercise of activity as an air carrier (i.e. they need to board the passengers using the mobile stairs).

This was the point I wanted to make about the expectation that a plane operating our of CDG at certain times of the year is (as part of normal operation) required to be de-iced and any airline would need to have procedures in place so that the de-icing process does not cause delays to the scheduled departure. Now if a sudden blizzard happened in the summer this same expectation would not exists, thus extraordinary.

Also, scheduling a flight to operate earlier doesn't really solve an EU261 delay since it's based on arrival at final destination. In this case it would have helped the OP not miss the connection, but it would not have absolved CX had there still been a delay greater than the prescribed 4 hours than the now earlier scheduled arrival time (by virtue of moving the departure time).

Now the airline can try to counter claim against the deicing service provider for having to payout EC261, but I doubt these kinds of things make it out to the public purview if ever they occur.