I really hope you read this gently. (As the HN guidelines say, "Please respond to the strongest plausible interpretation of what someone says, not a weaker one that's easier to criticize. Assume good faith.") I'm not trying to talk down to you or treat you with hostility (and I know that it's really hard to convey that via text). I would just ask that when someone who has professional, real-world experience in something says it is difficult and time-consuming to do it right, you'd avoid assuming they just don't know what they're doing, and that perhaps there are aspects that you haven't considered.
And hey, maybe you or some of the other commenters are just ridiculously smart and focused and can write it in a weekend. But if that's the case, it's pretty uncharitable to push a narrative that it's trivial. Not saying that's what's happening here, but that could be how it's coming off.