Flaticon requires you to attribute each author:
In order to use an icon you must attribute it to it's [sic] author, so we will be able to continue creating new graphic resources every day.
Icon made by [author link] from www.flaticon.com
E.g.: Icon made by Freepik from www.flaticon.com
From a legal perspective: The icons are under copyright by their respective creators; you cannot legally use them without permission. You can't have permission unless you follow the rules the authors have laid down for reuse of their work.
From an ethical perspective: Attribution is not a punishment, or merely a way for you to admit that you didn't create 100% of the visuals in your project. It is a mechanism to give credit to the authors who created the work you're using. The authors generously let you use their work for free; they only ask that their names and site links be included.
Flaticon is a repository of work from various artists, and saying where you found an artist's work isn't the same as attribution. By saying "Icons provided by various Flaticon users," you are not attributing the authors, but giving a hint about where a user might be able to hunt down authorship information. This is about as useful as (or perhaps even less useful than) simply putting a notice in your project like, "I found some of these icons on the Internet; if you put them into Google Reverse Image Search you might be able to find out who made them," and calling that sufficient attribution.
Fortunately, even if your attribution list is very long, Flaticon allows you place your attributions very unobtrusively. Their suggestions include:
Insert the attribution on the page of the icon (for example in the page footer) or on the imprint page.
Paste this attribution on the final work so the authorship is known (for instance, in the acknowledgements chapter of a book)
Place the attribution on the credits/description page of the application.
In all cases, you are allowed to place all of your attributions in an appendix, rather than directly alongside the image.
If attributions are for some reason too onerous for you, and you would rather pay money than deal with attributions, you can pay for a Flaticon subscription plan which allows you to use most Flaticon resources without attribution. (Resources licensed only under Creative Commons appear not to be covered by the for-pay plan, which appears to grant rights to works under the Flaticon Basic License.)