> you must necessarily provide justification so that another audience, which would want to make sure that you're not selling snake oil, could verify your why
Much of the audience that has the expertise to effectively verify the wisdom of the advice in such a document will have already encountered the views it contains and will be familiar with the reasoning behind those views already. None of the guidance in the article is likely to be something they're hearing for the first time. Even if they disagree with something in the article in whole or in part, they already know why the people who compiled the article likely believe it.
It is good for there to be more detailed explanations for interested non-experts, and there have been a number of more detailed explanations of many of these items elsewhere on the internet. But for most people it's more important to know that, for example, a recent iPhone is their best choice for a secure phone than it is to know the details of why experts on the topic have come to that conclusion, just like it's more important for most people to take a flu vaccine each year than it is for them to understand the process by which that vaccines was formulated.