It is not required that a web site or app have a ToS document at all. If it does, there is no requirement that it use legal terminology. A ToS is where the site operator or app maintainer defines the policies that will be used, and spells out rules that users must follow. In some cases it will be a legally binding contract between the operator and the users, and users are often required to agree to it before entering the site or signing up for an app or service, or creating an account.
The answer by user6726 (which is quite good) discussed situations when an operator might want to remove and block a user. By default, a site or app operator can block any user for any reason allowed by law. But when users have a contract granting them access, and particularly when users have paid for access for a specific period, the contract (which generally means the ToS) needs to specify the reasons or circumstances when a user can be removed or an account can be cancelled.
The good reason for using legalese is because it is language that has been tested in previous legal cases, and it is easier to predict how a court will treat it. It should be clear and specific. (A bad but common reason for using legalese is because "everyone does it" and it may impress users and be unclear to them.)
Ideally a ToS document should be clear to users, letting them know just what is offered tom them and what is expected of them. It should also be clear to any court that may be involved if a dispute ever gets as far as a lawsuit.
A lawyer who has knowledge of the relevant specialties can choose language that will serve these purposes, and cover remote as well as likely contingencies. Such a lawyer can also choose terms and phrases that have been tested ion court before, and whops meaning in legal terms is clear.
A good generator program can incorporate the knowledge of one or or such lawyers, also producing clear and tested language. In either case a well-drafted ToS will increase the predictability of the outcome of any dispute, and thus reduce the risk of a suit being brought, and the risk of losing if a suit is brought.
A ToS drafted by the developer or operator may be clear, but may not use language tested in court, and may not deal with situations that the author has not thought of, even though they have occurred before and need to be addressed. Thus it may increase the legal risk toi the operator.
There is nothing magic about legalese. Often the best legal documents use relatively little of it. But it can be very valuable to know what terms and phrases have been tested in court, and what effect has been given to them in the past. It can also be very helpful to be aware of situations that have come up in the past, or that might come up under current law. A lawyer with good IP and IT knowledge may be aware of many such situations. A well-written generator program should incorporate such knowledge. A poor lawyer or a poorly-written generator may create a ToS document that is worse than the developer would do on his or her own.
