Living Christianity is not just about learning theological facts and giving each other advice. It is also about helping people practically - feeding the hungry, clothing the naked and all that - which you cannot do with a keyboard. Local fellowship gives you the connections with real people who will actually be able to turn up with a hot meal when you're sick, and vice versa.
Remote fellowship is great too, but it does not entirely substitute for local fellowship, the need for a local church of some form.
Acts of love, physical service to our fellow man, does not require a body of believers, but just yourself, filled by the Spirit. We are surrounded by people who we can serve and in so doing be a witness to them of the love of God. And we should. So, I agree with your first paragraph. In fact, Jesus admonished those who only did good things to those who did good things back to them. But all of that is beside the point of "do not neglect the fellowship of believers", which is often the 2x4 used to both browbeat absent members and prop up the concept of the regular amassing of Sunday club members in a temple built by human hands, which is to say "going to church", and so sits completely off to the side of what I was saying.
But then your second paragraph attempts to shoehorn the first one into a conclusion that we need that local "church" in order to achieve it. I cannot agree with that. The reason why
believers have a special need for fellowship amongst
eachother has nothing to do with "feeding the hungry, clothing the naked, and all that" because those afflictions are not unique to us, nor are we the only ones who can treat them. The reason why we specifically should fellowship with eachother specifically is because of something unique to us that sets us appart from other people and can benefit from mutual support. I'll let you fill in the blank. It should be clear now. And the reason the wording is cautionary to not neglect it, rather than setting out times and seasons to do it, is that it isn't supposed to be religious attendance. It's supposed to be whenever and wherever and however it is needed. Judge for yourself what Christian fellowship looked and looks like when you strip away the sugary top layer of State-sanctioned organized religion. See the form it takes when it's been humbled and refined by fire. It's irregular, prone to persecution, not idolized, and precious wherever you can find it.
That is the basis of the fellowship of believers. All else is fluff that quickly becomes idolatry.