Siegfried Linkwitz is the guy out there making foolishness out of all the "narrow dispersion is good" silliness. Maybe it's good in a PA, but not a living room. This crowd here deliberately avoids and ignores anything that disagrees with their OPINIONS. That's the source of this controversy.
You're trying to make factual a supposedly overriding sonic flaw with horn speakers with reference to their dispersive nature of directivity - because you heard all or some of them and suddenly finds it a compelling conclusion to deliver? Or, because it's a convenient (albeit irrelevant) theoretical stance that requires little on your part? Why is narrow dispersion a bad thing with speakers in domestic environments? Edge diffraction - does it occur with all horns, and to what extend does it really matter going by actual auditioning? Does any sought theoretical explanation correlate with your actual listening experience in this regard, or rather: how would it? Any other theory-laden straw man you care to pull from your magic hat?
There was a time when you indulged - to a limited extend, one might add - in this discussion from an outset of actual LISTENING experience (the only thing that matters, right?), or to give it a chance with a range of or certain horn speakers, which in fact always comes down to OPINION. So please, don't try and direct this to where the proponents of horn sound avoid the arguments of anyone in disagreement, but rather see it as a reaction to any want of equating horn sound as a whole with a factually based flaw - one based on theory, no less. This is becoming trite. Move on.