They use weapons extensively because they're overwhelmingly barely physically capable of the role (https://www.newsweek.com/dhs-responds-report-ice-recruits-fa...) and get 8 weeks of training with no military or law enforcement experience required (https://old.reddit.com/r/ICE_Raids/comments/1mrdh6r/fyi_ice_...).

You can read any mainstream source to find out the general contours of the situation. The "want you to understand" is in the context of there being too many people in outright denial about the naked autocratic fascism that has descended upon our country - eg see all the comments in this very thread trying to justify any of this as being about "the law" or "illegal immigration".