Author Josef Zbořil gives three reasons, the first one has to do with the monetary system and the Czech peoples unwillingness to bail out countries like Greece, but it’s the next two reasons that interested me the most.
Here are a few snips from the Gatestone article entitled:

Integrating Islam or Islamizing Integration?

If polls are to be trusted, one of the next countries most likely to follow Britain’s lead and exit the European Union is the Czech Republic. In 2016, after the Brexit referendum, a mere 25% of the Czech public said it was satisfied with membership in the EU. There are three main reasons for this dissatisfaction.

[….]

The second reason for Czech dissatisfaction with the EU has to do with the desire to retain a national identity, rather than blend completely into a general European “One”.

[….]

The third reason for Czech concern about the EU is that although its original aim may have been to establish inter-European integration — with mutual tolerance and respect even with and towards non-European cultures — it is becoming increasingly evident that immigrants from Muslim countries do not spontaneously integrate. On the contrary, there has been a controlled Islamization of integration, rather than the other way around.

The fear among Czechs is that such a trend will lead, within a few decades, to a dangerous demographic shift and ultimate theocratic totality in Europe as in the Middle East.

This fear was expressed by figures such as Tomio Okamura, the leader of Czech Freedom and Direct democracy party, whose slogan, ahead of the Czech parliamentary elections in 2017, was: “No to Islam. No to terrorists.” Even former social democratic Prime Minister Bohuslav Sobotka stated: “When we see problems in other European countries, we no longer want Muslims in the Czech Republic.”

The “controlled Islamization of integration” was confirmed by the Organization of Islamic Cooperation in November 2000, in a document entitled “The Strategy for Islamic Cultural Action outside the Islamic World,” which states:

“The demographic constituents of western countries… will change and become subject to restructuring into a multi-ethnic and multi-cultural society. Thereby, western countries will no longer remain that harmonious and monolithic society constituted on the basis of a specific historical, economic, social and cultural lineage….

“Sensing the importance of Islamic communities and minorities in the west… immunize the second, third and even fourth generations of those communities, who settled outside the Islamic world, against cultural assimilation and loss of their Islamic identity.”

[….]

If European integration is to succeed without submission to Islamization, Europeans must choose the path of freedom, and replace empty phrases with practical steps.

More here.
In my opinion, the only practical step that will work is to not admit the hijra-driven Muslim migrants in the first place!
It is demography, demography, demography!
See my whole ‘Invasion of Europe’ archive.