After 2nd round of review (R1) for almost 2 months, I received a sharp rejection letter for my manuscript (in biology) submitted in a certain journal for language-use concerns and formatting issues. Nearly 80% of the comments raised by reviewer #1 and the editor (I think they are one person in this case) are mainly the use of British-English and formatting, but the journal has no clear policy of the English-use as long as style and punctuation is consistent throughout. English is my second-language but we use it in universities and communications, however, I believe the language concern is not an issue as my co-author (my supervisor) is a native English speaker and we proofread the paper many times before resubmission. Our personal assessment based on experience with other journals, this concern should at least be major or minor revisions.
It is hard to see how ethics enters in to it. Had you paid them something and they rejected it, keeping your money, then it is a different matter. But a submission is just an offer and it can be rejected for any reason. It may not represent the best policy in general, but it isn't unethical.
And, perhaps there are other issues as well and they all piled up to indicate a reject. That is impossible to judge without more information that only you and the editor might possess. It might be as simple as not wanting to do a third round.
This would be pretty inappropriate. If they are objecting on language-based issues, unless you inserted all the issues during revision (unlikely), they could have rejected immediately, before even inviting a reviewer. If they didn't they could certainly have asked you for corrections during the first revision. As it is, they've simply wasted time and reviewer resources.
A few caveats:
- As Raghu Parthasarathy pointed out in a comment, based on your description, you don't actually know if your manuscript was rejected because of language issues. Taking up 80% of the review doesn't mean it was 80% of the reason your manuscript was rejected.
- In the same vein, even if the remaining 20% of the review was not bad, you can't tell if there are confidential comments the editor isn't sharing.
- If the reviewer pointed out language problems in the first review which you didn't amend, they could be annoyed enough to recommend rejection (see gnometorule's comment).
Having said the above, you write in a comment that the editor did say they are rejecting because of language issues. In this case, I think there's a fairly good chance that an appeal will be successful. You could try filing one, pointing out that the objection is not for scientific reasons and the paper's language is already fairly good.