To say you "can't unsee" something is equivalent to saying you can only see one thing; i.e., admitting you don't have an open mind. Consequently, this lens is causing a serious problem. Many analogies come to mind. Think of the Lord of the Rings movies, when the wearer of the Ring is portrayed as "moving through a shadowy realm where everything is distorted." That's what the Mesoamerican lens (or lenses, spectacles, etc.) does to those who look through it. It turns them into Mesoamerican "seers."
The Church is officially neutral on the question of Book of Mormon geography--a wise and appropriate position.
The problem is that the Mesoamerican seers dominate LDS scholarship and publications and media and institutions, including CES, BYU, etc. They carefully fit the lenses on their students, starting in Primary, so that by the time students reach college and beyond, many of them, too, "can't unsee" Mesoamerica. But when an event yanks off the Mesoamerican spectacles--such as an encounter with an Internet page, a skeptical investigator, a former Mormon--the fallacies of the Mesoamerican theory become apparent. Having never been taught, or even exposed to, an alternative to the Mesoamerican setting, unsuspecting but once-faithful members too often jettison the Book of Mormon along with the Mesoamerican theory.
I have no problem with people believing whatever they want to believe, in the spirit of Article of Faith 11. My problem is the Orwellian suppression of alternative views by LDS scholars. They deprive their readers, hearers, and students of the opportunity to make an informed choice about what to believe regarding Book of Mormon geography and historicity.
To understand why, it's helpful to look at how the Mesoamerican lenses operate. They turn wearers into "seers" who
1) see Mesoamerican terms in the text that are invisible to those not wearing the lenses (which leads to them using the Sorenson and other translations of the text instead of Joseph's translation);
2) are unable to see any evidence that contradicts their theories (the Mesoamerican lenses blind the wearer);
3) interpret Church history to cast doubt on the Three Witnesses and other important statements;
4) use rhetorical sleight of hand and logical fallacies to perpetuate their theories;
5) participate in a citation cartel that excludes both consideration and exposure of facts and analysis that contradict their theories.