I find these speeches, marketing efforts, etc. offensive and disruptive. Having stated that, the shul has a gabbai who is in charge (as is often quipped, the gabbai is the one who calls the ש”ץ). One may not assume that the desperate and charitable cause he is collecting for authorizes him to make an appeal without express permission from the gabbai.
Equally as impossible to tolerate are those who believe they are permitted to disturb the Baal Tefiloh, and those of us who may saying Kriyas Shema or Shemoneh Esrei. I suspect that those who disrespect tefiloh to that degree are not legitimate, and are either non-Jews or are drug addicts expecting our generosity to subsidize their drug use. This is not radical – it has been observed quite a bit.
This brings to mind the campaigns typical to Purim or before the Yomim Noraim in which yeshiva boys and bochurim are sent to collect in batei medrash. There should be some way to insure that these collectors are trained prior to their missions how to do so respectfully, and without disrupting tefiloh.