What is important to grok is that these are not really all that different, at all. This is the salient point. The intent to hurt ‘the other identity’ is straightforwardly derived from, and consists entirely of, the base instinctual aggression that is the same in humans and other animals (as humans are animals too).
Whether the harm is intended for a ‘good reason’ or not is a smokescreen, a diversionary tactic. Many a human over many a millennia has justified their aggression as being for a ‘good reason’ (and therefore not attaining to malice* as you use it [malice* with a * will mean “malice” as you use the word]). But it just doesn’t matter. The point is to be free from aggression entirely, not just malice*.
I know, but by looking at only a tiny part of the picture - malice* - and not the entirety of the picture - the mountain of aggression immediately under it - you are missing the whole point.
It’s not a tangent, it gets right to the heart of the matter. The instinctual passions are not only the ‘ultimate reason’ for an identity forming, they are the ongoing, moment-to-moment reason. Each time you feel a social-identity-level desire to hurt someone or be snippy or sarcastic, that is a direct manifestation of instinctual aggression. It is not something ‘on top of it’ that is somehow unrelated to it. It doesn’t acquire a different character just because it may be socialized or learned and you don’t come out of the womb being sarcastic. It is just a shape that instinctual aggression takes – one of the many possible shapes.
The reason to repeatedly invoke it is because of how this thread started:
That is, you think harmlessness is not a doorway to happiness, because in your experience you can be happy while you are not being harmless (i.e. you can be happy while being aggressive and maybe even mailcious*). (Note that in actualism terms “harmless” refers to being without aggression at all of any form, and not just to being without malice*.)
The point is that aggression is so thoroughly what we are, as feeling-beings, that an overriding and overarching desire for harmlessness (and not just happiness) is required, in order to be able to have any shot of dismantling ‘me’ in order to eventuate a consistent feeling-good come-what-may.
So you have to grasp that whatever fine-level distinctions you can make between the basic aggression on the one hand, and malice* and any other specific subsets of aggression that you can think of on the other, it just doesn’t matter in the grand scheme. The problem is not malice*, the problem is aggression. The only way to counter it is by actually wanting to and intending to be harmless, in addition to wanting and intending to be happy.
If you try just to be happy without being harmless then you won’t be able to answer obvious questions such as:
The answer obviously is… establish a desire and intention to be harmless! Then when you find yourself with a sharp verbal barb ready to unleash, you can see via feeling it out that you are feeling aggressive, and perhaps malicious*, you can see that this will obviously be a harmful thing to express, and then you can choose not to express it in order to fulfil your intention of being harmless!
Then later maybe you can see that even the feeling of being aggressive or malicious*, in and of itself, already is intrinsically harmful, due to the vibes and psychic currents unwittingly emanated, not to mention any unconscious or subconscious reactions that you can’t control, and you can use this as motivation to see how ‘you’ tick so that you don’t even have that initial feeling of aggression arise in similar situations.
I would certainly recommend just trying it. One really obvious example in my experience was, approaching social interactions with an intention of having a smooth or ‘good’ or sensible or straightforward interaction, vs. approaching them with the explicit intent of enjoying it and being harmless in the interaction. The former led to cases where I would get annoyed or peeved when there were misunderstandings or awkward interruptions etc. The latter led to these not mattering whatsoever, being more intimate, more understanding, and having a much better time with people.
Once you start doing so you may even see how you are noticeably and palpably happier, now that you are more harmless, and then you can see for yourself how the more harmless you are the happier you are, and you can combine that with what you already saw (that the happier you are the more harmless you are), completing the positive feedback loop, and let that take you away to more and more stratospheric levels of enjoyment and appreciation.
Ooooor you can keep insisting, despite many people who have more experience than you in the matter saying otherwise, that harmlessness doesn’t really matter 
. The choice is yours.