Is that racism? In that case I have been subjected to it many times even in my country of birth (the Netherlands) by speaking ABN ('algemeen beschaafd Nederlands', meaning not a local dialect but the type of Dutch spoken by the king or queen) in a place like Limburg (the southern-most province) where they tell me 'Ich spreck niet met hollanders!" (literally "I do not speak with people from the province of Holland" where "Holland" is meant to be understood as "not from the southern provinces") in an angry voice. I can understand the Limburg dialect since I speak German as well as Dutch and Limburgs lies somewhere in between (depending on which local variety, sometimes it seems more German than Dutch). This is only within a single tiny country, if I set my foot outside of it and make the mistake of starting to speak English in France I'd often only be met with feigned misunderstanding or foul looks by people who understand me perfectly well but consider their language an integral part of their identity and as such feel that others should make the effort to use it when communicating with Frenchmen. Were I to start in halting French we'd often end up speaking halting English without any bad feelings. Is that racism? No, it is not. It it a form of chauvinism, a way to mark people as not being part of their group. It is not racism since they do not react to my "race" (skin colour, facial features and whatever else is linked to "race") but to the way I speak. I could have spoken Limbursch or French and avoided their reaction. I can not change my race while I can change the way I speak if I so desire.
> If you are a white European, you will have a hard time seeing racism, compared with people who are not white.
That is a racist statement in and of itself, and you do not even know whether I'm a "white" European, let alone the fact that "white" means just as much as "black" when it comes to indicating the culture people grew up and live in. Since I can only assume you are not a racist I assume you made that statement because it is part of the current narrative - it is called standpoint epistemology [1], part of critical theory - without really giving it some thought.
If you agree that racism is used as a political weapon it is only prudent to make sure you do not unwittingly make yourself become a part of that weapon.
Yes, people tend to react differently to people depending on whether they are from their own group or from the outside, up to and including to telling them to "go back where they came from". This is said to Polish migrant workers in western Europe, to Palestinian migrants in Syria, to Koreans in Japan - in all cases you'll be hard-pressed to find any "racial" differences between the groups. It is chauvinism, nationalism, protectionism or just fear of being overrun by "the other". It is not racism and should not be called such, specifically for the reason you yourself mentioned: racism is being used as a political weapon.
[1] https://en.wikipedia.org/wiki/Standpoint_theory