I can't recognise the word "coward" any more than I recognise the words "selfish" or "evil"; all these words seem to be extremely subjective to the point their application is predominantly by white knights who want to dismantle others for doing things they, themselves, personally disagree with i.e. when pro-lifers deem suicide "selfish" because of its impact on others, they fail to acknowledge the fact that others' dependency on that person staying alive can similarly be seen to be selfish; if suicide is "selfish", then so is dependency. "Selfish" is therefore not a word of any real substance, it's just the go-to word of choice by pro-lifers hoping to instil enough guilt into the suicidal that they are deterred from making such a decision for themselves that could have an undesirable impact on others.
"Coward" is the same kind of word. It has no substance. Antagonising others behind a screen is cowardly? Then so are most real-life instances of antagonisation; the only difference is the type of 'protective layer' behind which the insults and bullying is launched. So in the real world, instead of having a computer screen as protection, the antagonist's protective layer now becomes their capacity to intimidate by being bigger/louder/stronger than their victim (also relying on the victim's weakness and ease of subjugation). That's the same as the cowardice of antagonising online.
So whenever someone moans about the cowardice of so-called keyboard warriors on social media, saying "I'd like to meet these people in the flesh", their proposed method of altercation is actually just the physical equivalent of the thing they are supposedly damning. The ability to be more physically aggressive and using this to one's advantage is the same as if they had derived such an advantage from being more offensive in typed word.
Basically, the internet hasn't made people anything, "cowardice" (or its relative meaning) has already long ingrained itself into society but in different forms. The internet has only made this underlying negative aspect of typical behaviour more transparent, but this aspect already existed.
tl;dr keyboard warriors AND mouth warriors are both shit. /rant of the day