It means you are describing something as the most typically Dutch thing imaginable. Seeing Dutch football fans with Swapfiets bikes in the US is a playful way to say that scene is quintessentially Dutch. The phrase is affectionate hyperbole, not a literal measurement.
What makes the scene read as extremely Dutch? Swapfiets is a Dutch bike subscription service with a recognizable blue front wheel and a practical carrier. Dutch people are known for cycling everywhere, for using simple and functional bikes, and for bringing their everyday habits with them when they travel. When football fans show up abroad with those specific bikes, it combines national pride, cycling culture, and a sense of pragmatism in one image. That is why someone would say you cannot be any more Dutch than that.
You will hear similar phrases like "That is so Dutch" or "You can't get more Dutch than that." People use them when an action, object, or situation seems to capture something culturally familiar in a positive or humorous way. For example, eating hagelslag on bread, bringing your own snacks to a birthday party, or biking into the wind instead of driving. It is a way of noticing identity through small, everyday details.
There is an honest tradeoff to keep in mind. These phrases rely on cultural stereotypes, so they work best when used lightly about a scene or behavior, not as a serious statement about an individual. If you say it to a Dutch person, many will laugh and agree, but some may push back because no single experience represents everyone. In conversation, it is safer to aim it at the situation rather than at a person's character.
If you want to understand this kind of expression as a learner, the best next step is observation. Notice how Dutch people talk about biking, weather, food, and directness in everyday life. Listen to Dutch podcasts, watch football interviews, and read Dutch news out loud. When you hear a phrase like this, think about the image it creates, not just the literal words. If a native speaker tells you that something you did is "very Dutch," you can take it as a friendly observation and respond lightly, for example "I'll take that as a compliment." The more you encounter the culture through real examples, the faster these expressions will make sense.