But we cannot expect non-native English speakers to participate into higher end discussions.

Just imagine a non-English 20 year old boy joins here and enter the general discussion board, if he finds a topic bitcoin is money or investment, he will try to say something but if he sees ONLY discussions like high technical subjects for example about segwit, he will probably close the tab and will open facebook page.

In long run we may loose a possible bitcoin adopter.

If bitcoin is only for native English speaker then we can have higher standards for topics and posts.
(still I doubt they will be ready to talk for tech topics)

Obvious spammers/ copy pasters must deserve their ban. No second opinion on this.