But the size of the universe that we can observe planets in is not even approximately infinite. The number of stars within the range we can observe planets in is only about 1e+9 (!!). Small planets like the one in question are much harder to observe and could not plausibly be discovered at that kind of range, so maybe only 1e+6. We have only actually observed the tiniest fraction of that, so much smaller. That 99.99999% would suggest that this planet should not have been discovered. Even if it were 99.99%, I suspect we wouldn't have found this planet. The outliers we're finding at the moment shouldn't be *real* outliers, not in a galactic scale.
You need to learn the math of percentages better and appreciate the size of the galaxy and the universe that we live in. even 0.01% of one million (1e+6) is a hundred planets. Bear in mind that the most distant exoplanet we've detected so far is in a different *galaxy* (21500 +- 3300 light years away) that puts a massive number of stars within range - certainly billions, possibly trillions, not just millions. Remember that there are estimated to be 400 billion stars in the Milky Way alone. Do you truly believe we can only see one out of four hundred of those stars?
When you're dealing with numbers on that sheer scale, you can be fairly sure that even if there's only a minuscule chance of something happening, it will have happened many, many times.