People are always reluctant to answer these kinds of questions because feelings can get hurt. In my view, I always prefer full disclosure when answering a question as it helps add more context to the (2nd) question that you've asked when I may not have seen the original or recall it if I did.
That having been said, if you feel your original question didn't get the attention it deserved, that's also what a bounty is for. You had the option of putting a bounty of 50 points or more on that question to bring more attention to it.
I personally recall nearly making the comment on your original post that if the last name, email and phone number all matched, there didn't seem to be any reason to also need to require a match on the first name too. I don't recall why I didn't except that I must not have had time.
As an example, people will use their first initial at times or "Robert" will also use "Bob" at times etc., giving the appearance that you have two unique leads when they're clearly the same. These days almost no family shares the same email address between spouses or parents and children. And if they did, wouldn't they still be the same lead? Look at how many kids have their own cell numbers.
I think the feedback you were receiving on your original question was saying, before investing time in creating your own tool (in essence, reinventing the wheel), go and try the new built-in deduplicating tools provided by Salesforce. If you're not satisfied with those tools, sure, roll your own and you'll know what you want to do that's different than the standard tools available to you.
That's my view of what transpired. Hope this feedback is helpful to you.