So yeah you need ego. That said, it must also be tempered with the reality of needing to compromise enough to satisfice all stakeholders (including both technical and business stakeholders of all the different flavors). The beautiful thing about software engineering though, is there is a reasonable amount of objective facts, metrics and tradeoffs, that given a critical mass of sufficiently skilled and mature engineers, common ground tends not to be too hard to align on. Or at least, far easier than to get a non-technical stakeholder to understand the long-term implications of a bad decision.
To make the best work you have to take pride in it. This work has my name on it, customers will use it, I want to improve their lives not make them worse.
The developers who come after me will need to assimilate this work. They'll need to build on it. I want to make their work a joy, not a burden.
Do I take pride in what I do. It's not enough that the code just compiles.
Pride is balanced by humility. I'm prepared to defend my choices (with well informed, well experienced) answers. But the choices I make are always a balance of upside and downside. And over my career things have changed which reweights some of those decisions. I'm open to external input from others because I want the result to be good not me to be right.
I want to be proud of my work. But I'm humble enough to let others help me to improve it.
[The above is my goal, sometimes I fall short]
There are 19 pairs of vice/virtue pairs in the ego. We can only decrease our ego's vice-eous tendencies by increasing our consciously manifesting compassion to everyone we encounter. It also helps to contact our Creator and ask for guidance. It awaits us in Its Unfathomable Lonliness to beseech it for help to begin and then see out the complete transformation of our ego into a selfless, servant of the happiness of others and the societies/cultures we inhabit.
That Path of Loving Service is the key to happiness, and is the opposite of narcissistic attitudes and bahaviors.
There is nothing mysterious about the ego; it's just that willful ignorance is one of our heart's vices, and its purpose is to deny that each person's ego transformation is not only possible, but the source of joy and community uplift, and is our free will to choose love or any of its many selfish opposites.
The same sadly has happened with confusion of the word selfless (having no concern with self) with unselfish (concerned with others before oneself) and altruistic (unselfish concern for others' well being).
Personally, I don't see any incompatibility between having a sense of self and healthy self-esteem and having compassion.
Indeed, I see a major incompatibility between actual selflessness and universal compassion - as selflessness would preclude compassion for oneself.
You're right about the negativity of the ego's self-important nature via conceit and egotism. Those are negative traits of the self. The goal of self-improvement is to become a consciously virtuous person who puts the needs of the whole in its proper place, and doesn't indulge their selfish vices, which always cause unhappiness to those around them.
Positive self-esteem, when due to being a compassionate person, is a necessary component of the self-evolving person, because honesty in grokking the truth of ourselves is an important part of our growth.
And, remember, universal compassion also includes being compassionate to our own self, and as we increase our virtuosness, we are ever more beloved by the universe, itself. The happiness on that path is not known by but a small minority of the world's cultures/societies.
Sorry I'm not writing so clearly this late in the day, but know that the ego we have a birth is mostly selfish. It takes a definite turn towards the light to begin the process of purifying it by degrees from egotist to self-actualized bearer of compassion. It's a true fight, fighting against our own fallabilities and weaknesses and selfishnesses. But it's the most worthy struggle we will ever undertake.
There is nothing wrong with taking pride in your work, nor in recognizing that you might actually be more knowledgable/skilled/correct in some particular matter than someone else and communicating that to them - as long as that sense of knowledge/skill/correctness is not misplaced, not expressed cruelly, and the actual reasoning is explained. To me, that is "good ego". But if someone thinks they always know better than someone else in all cases or isn't even willing to open discourse/explain why that's "bad ego".
I guess to me, the sentiment expressed in this article is one that I feel strays too far into the realm of toxic positivity or crabs-in-a-bucket where merely being opinionated or passionate about your work is a bad thing because sometimes other people get their feelings hurt when you explain why their approach won't work well. I just don't think being egoless is necessarily good. I certainly wouldn't sit there smiling while something I worked on for years got destroyed by other people, because it'd be impolite or egotistical to point out that their destroying something. But of course, there is a difference between something actually getting ruined, and having a meltdown because someone started naming variable in snake_case instead of camelCase.