I maintain that you should consult a dictionary before telling someone what they should have said. Also, we all make mistakes; the thing is to own up rather than doubling down.
Just because a definition -technically- exists doesn’t mean it’s actually used very much, or is the main definition the word is used for. “Public discourse” is correct, at least for Standard American English.
edit: I am not arguing that this definition doesn't exist. As a native speaker I'm saying that it is very rarely used, if ever. A correction to "public discourse", a statement that actually -is- used by native speakers with frequency, is perfectly reasonable. Communication isn't about being technically correct in order to win arguments.
You have to be deliberately not looking:
https://books.google.hn/books?id=T0E8AAAAIAAJ&pg=PA88&lpg=PA...
https://www.jstor.org/stable/25119912?seq=1#metadata_info_ta...
https://hansard.parliament.uk/Lords/1852-06-24/debates/dd891...
These comments about this common word are more suited to the middle school lunchroom than a forum such as this.
We're stating the fact that that specific usage/definition is not really used at all anymore, to the point that "intercourse" is generally used for the other definition of sexual activity. "Public intercourse" is significantly likely more to be read as "public sex", rather than the intended meaning of "public discourse".
It is perfectly reasonable to suggest a correction, because communication with people is about understanding... not being technically correct to win an argument.
You can check out the usage of these two bigrams via google ngram yourself: https://books.google.com/ngrams/graph?content=public+interco...
it's actually not though.
> As a native speaker I'm saying
Wow, how presumptous!
What does that even mean? Did you know that the language is spoken across so many continents?
Are you American? British? Australian? Something else?
Do you know the number of Indians who are 'native English speakers' in that English is their #1 go-to language to read/write/think in? (even though they know a few others? )
> Do you know the number of Indians who are 'native English speakers'
Probably more than the population of the US.
The only time I've ever encountered this usage of public intercourse is in older texts. Certainly no one my age would use that instead of "public discourse".
And that has nothing to do with levels of education or "childishness". One can be highly educated and have a diverse vocabulary while acknowledging the fact that certain usages are more popular than other usages, and they can change over time. Languages are illogical and beautiful in that way.
Well, maybe not so much, but I assure you, the number is in the millions.
Native speakers of Indian English or British English have different vernacular, colloquialisms, etc, which is why I specifically commented on Standard American English.