Yes, absolutely, and it is important that the GPL allows this.
First, the FSF encourages people to sell free software when possible (emphasis mine):
Actually, we encourage people who redistribute free software to charge as much as they wish or can. If a license does not permit users to make copies and sell them, it is a nonfree license.
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Free programs are sometimes distributed gratis, and sometimes for a substantial price. Often the same program is available in both ways from different places. The program is free regardless of the price, because users have freedom in using it.
It is certainly possible that the situation you describe is predatory, insofar as it sells for a fee what could easily be had without a fee. But that may not be generally true for this category of behavior, and this specific case may not even be particularly predatory.
To you, the availability of this software in the Microsoft store is not valuable, so you would not pay money for it. That may not be so for someone whose nation's firewall or whose employer's system policy forbids downloading or installing software from particular places. If Microsoft's store is the only place they can get the GIMP, they might happily pay the fee rather than figure out how else to get it.
Even if that's not actually true of this particular case, it is true of similar cases. The ability to redistribute the software through different channels (and compiled to run on different architectures) is important to ensure enduring and widespread availability of the software, and the GPL allows redistributors to charge money to do so. The GPL, as a legal tool, cannot distinguish between "predatory" and "non-predatory" prices for any particular act of redistribution; we can only rely on the market to sort such matters out.
If you object to the price being charged for some free software through some redistribution channel, the GPL (or any free license) gives you the freedom to build and offer your own copy for whatever lower price you want. In this way, the price will eventually (but not instantly or uniformly) approach zero across all distribution methods.
Note that any particular distribution channel may impose GPL-incompatible requirements (see another answer on this question that explores this extensively), but there is no problem in general with compiling or distributing GPL software for a fee.
