What utm_campaign actually is
utm_campaign is the tag that names the actual initiative a link belongs to: a product launch, a seasonal sale, a specific email send. Where utm_medium says what kind of channel a click came through and utm_source says which specific place, utm_campaign says which effort it was part of, and it's the field most reports are grouped and compared by, since "how did the spring launch perform" is usually the question someone actually wants answered, not "how did cpc perform" in the abstract.
It's a label, not an identifier
Everyone who clicks any link tagged with the same utm_campaign value gets grouped under that one campaign name, the same way everyone who clicks any link tagged with the same utm_source gets grouped under that one source. Nothing about the value is generated per click or per person; a marketer types it once when building the link, and it stays fixed no matter who clicks or how many times.
The naming mistake worth avoiding
Analytics grouping is exact-string and case-sensitive, so spring-launch, Spring Launch and spring_launch read as three different campaigns even though a person glancing at all three would call them the same thing. The practical fix is a consistent naming pattern, something like a date or year plus a short name, written the same way every time: lowercase, hyphens instead of spaces, no punctuation. The UTM builder checks new values against your own history and flags a near-duplicate before it becomes a fourth spelling of the same campaign.
utm_campaign versus utm_id
These get confused because they sound like they do the same job. utm_campaign is the human-readable name a person reads on a dashboard. utm_id is a separate, optional campaign ID that GA4 can pair with ad cost data you import. Most links only need utm_campaign; utm_id is worth adding on top if you import spend data and want those costs tied to a specific campaign.
Is it safe to remove?
Removing it doesn't touch the destination, only the campaign label attached to the click's attribution record. It identifies an initiative, not a person, so there's no privacy reason to strip it, only a reporting one for whoever built the link.