Joop, I'm sorry that I wasn't clear in describing the situation. There is far less certainty in that profile than you might have thought. The words in the profile were definitely not my words; I now know that they are the words of an anonymous author whose content was pasted into WikiTree.
The van der Kar-6 profile has a bunch of good sources (marriages and baptisms), but the narrative biography in the profile was completely unsourced. This is a problem we frequently have for New Netherland, where numerous profiles were created (sometimes we had many profiles for the same person, needing to be merged in spite of conflicting information) by people who often didn't understand sourcing (even many well-researched published genealogies of the past don't cite sources because the authors thought sources detracted from readability. These members eagerly contributed their received family trees (or someone else's online family tree) or text copied from a source that isn't identified. For a variety of reasons we don't simply discard this content (sometimes the content is valid, and even if it isn't, we try to respect the good intentions of the contributors). Instead of discarding their content we try to find reliable sources that confirm, disprove, or supplement the contributed content. The unsourced narrative in this particular profile looked like it might come from good sources (although it cited no sources, it described the types of information we often find in reliable sources). I asked "Does anyone happen to know where the "fact" collection on the Van_Der_Kar-6 profile came from?" simply because I was hoping that someone would know where the unsourced text originated. (I'm still hoping to learn more...) The bit about Utrecht Province is just one of the unsourced facts in the profile; I wondered if there was a credible basis for associating the name "van der Kar" (in any spelling) with Utrecht Province in the 1600s. This man's origin is mysterious because he first appears in records in 1687 with no mention of him or his family before then. Very few Dutch people came to New Netherland after 1674, so either he was born there but not documented until 1687, or he arrived later for some unusual reason. The firm statement that he arrived in 1685 from Utrecht province gave me the impression that someone had solid information about his arrival (maybe a contract for him to work for somebody). Sometimes the name(s) reported for a New Netherland family can be confirmed as having been abundant in the area the family supposedly came from. Thus, even if we can't find records for the individual, we can say that the claimed place of origin could be true. I think I've seen enough about the name to confirm that more than a few Dutch people in that part of the Netherlands used names like van der Kar, but that doesn't tell me where this man came from or when he arrived. With as little information as we have, it would not be productive to look for birth records for him.
As for when he arrived, there are very, very few passenger lists for ships that arrived in New Netherland. There was no modern-style organized government keeping records of immigrants. Our information on people's origins and arrival dates comes from marriage records that identify the person's place of origin, as well as letters, contracts, deeds, estate records, court minutes, church records, tax lists, etc., that record a person in a particular place on a particular date or show a New Netherlander's relationship to their Netherlands family. Even when we have something called a ship's list, that list may have been assembled from researching those other types of records.
As for emptying the data fields due to uncertainty, WikiTree doesn't like empty data fields. Because of the way data are handled, it is better to have a location that is labeled as "uncertain." We have been advised to name the country or continent when we cannot name the specific place, but with New Netherland people we may be more certain about specific places than we are about country and continent (maybe we are choosing between Amsterdam, Nederland; New Amsterdam, New Netherland; and Pernambuco, Brazil).