This is a relatively short list for due diligence. While far less dramatic than an engineering fault which could actually kill someone, there have absolutely been extremely expensive incidents in the US which occasioned each item on this list. A portion of them are due to peculiarities of doing business in the United States, which is organized to accomplish many forms of dispute resolution via a professionalized process backstopped by formal legal process, in a fashion which may not be similar to e.g. Pakistan, Japan, most European countries, etc. US companies do frequently generate more legal work than comparable situated companies in other jurisdictions. (There are varieties of work they generate less of, but I'll leave that out of the scope of this comment.)
The legal profession, like all service professions, sometimes recommends work which is not directly in the customer's interests, but in the main it is in the business of decreasing transactional risk. There are material risks involved in investing in a company with undisclosed baggage. Additionally, insisting on a certain level of professionalism helps to shake out other problems, because firms which cannot self-organize to e.g. provide a list of all employees and the paperwork related to them are almost certainly catastrophically managed under the hood. You might not even be creative enough to successfully predict how they're going to blow up, because the theoretical space of mistakes one can make is infinite, but you know that anyone who can't produce a signed copy of an employment agreement on demand is highly unlikely to have a level of risk which is roughly representative of your experience from the distribution of companies which are at least minimally competent.