A bit of philosophy:
Physics is based on experiments. The assumption is that the physical world exists and that we can understand it by experiments.
Over time we have created models that very closely describe the behaviour we see in the experiments. We use these models to make predictions of the results we will get from other experiments. But we are always aware that if we can create one single experiment that breaks the model we have to change our model -- the real world experiment result is the quality marker for our model.
Notice that the models never really answer the question why. The physical world simply exists and does whatever it wants to do. When we use a model we make it to get a prediction of something, but this is not a description of why.
Over time we have created more and more complex models, often to describe the edge cases. Well known example is the progression from Newtons laws of motion, over special and general relativity to quantuum mechanics. Newtons laws are quite good for a lot of things and we still use them, but gives wrong predictions at speeds approaching the speed of light. Special relativity is very good at a lot of things but gives wrong predictions at very small sizes of thing where we instead use quantuum mechanics. Newton laws of motion does not predict Heisenbergs uncertainty in any way.
In every day usage and in the process of learning things we often use simpler models than the ones at the forefront of our current learning. The reason often is that the models are complicated or use specialized mathematical tools that the student does not know yet.
To get back to the case of the Heisenberg uncertainty principle it is verified by experiments to exist and is well described by our models. So from that point of view, it simply exists and hence the model is a good model in predicting this part of reality. Any model that does not predict this behaviour is, if you take it as an absolute, a false model but can still be useful. If we compare it to Newtons motion laws we know they are false but they are still useful in everyday life.
The question why the uncertainty exists then becomes a non-valid question -- it simply is how the world works. I believe a better question to ask is how does this arise (or not) from predictions in our current best model. You see answers to that question in other posts here.
So to conclude. Experiments show that Heisenbergs uncertainty principle exists. A model that does not include this experimental result is either wrong or possibly a simplification only allowed give certain assumptions.
NOTE: a google search for "experimental verification of Heisenberg uncertainty principle" gives some insight in how the model can be experimentally verified. Hint: not easy. Hint 2: if you could produce an experiment that shows that the model is wrong and the principle is shown to be false, I guess you might be in for a Nobel price.