If someone thinks that Im rude, he/she could always send me a mail about that... But you must always remember too, that you have diff. culture than ours. For example... We do not have this smalltalk like you have (especially in usa), we don't use words like "(yes) indeed, please, ..." just for expletives, so e.g. when I writing something I say it just simply. It may sounds rude, but for me it's normal and those expletives sound unnatural/theatrical.
So, if some writes something that is incorrect, I'll probably say "You are wrong, because...." unlike you may say "In my opinion, I think you could be probably wrong, bacause.... Could you please check..."
So, of course, people who have used to hear these expletives may think that Im rude, bacause I don't use those "expletives". So something that is polite and just normal communication to me, may be impolite to you.