When you have strong arguments and proofs and you are saying the truth and that which corresponds with reality as well as revelation, then there would be no use in attacking the other person/party personally and using bad words.
That's why from the behaviour of the online supporters of certain groups we get an indication whether they are on truth or not, whether they fear Allah and are sincere or not!
Also when we listen to the speeches of the leaders of real mujahideen and their scholars, we see that they are always polite, very soft spoken, they come with proofs and evidences, from reality as well as revelation and logical and rational proofs.
But on the other side we see some spokesperson screaming, doing takfir, threatening, using bad words and attacking them personally, this shows that the behaviour and speech of this person or his supporters is not islamic and hence he cannot be on truth!
The Phrase Of Tawheed http://t.co/GcxG5EOV6g— Maiwand Al-Afghani (@ShabirMaiwand) 27 september 2015