Silo is a private tool. Its only user is its owner.
Silo reads the Gmail, Google Calendar and Google Tasks data of its owner. It uses read-only access. It cannot send, change or delete this data.
The data stays on a private server of the owner. Silo shares no data with other persons. Silo sells no data. Silo does not use the data for advertisements.
The use of data that Silo gets from Google APIs obeys the Google API Services User Data Policy, which includes the Limited Use requirements.
Go to https://myaccount.google.com/permissions and remove Silo.