I know this is getting very off-topic, but Japanese speakers would probably not write 左様なら either - it's usually written in kana: さようなら.
Back on topic, as a speaker of another language using Cyrillic, for me romanisation is perfectly normal/expected in this context. I don't expect English speakers to have to learn a new alphabet just to be able to read the title of a blog post which is otherwise in English.
