I just think it was inappropriate clothing for walking the streets in, speedos IMO are for the beach. To be fair to the guy he did have a nice bod, he wasn't some fat bloater or anything but he did stand out like a sore thumb and as has been said, the Goans do have modesty standards which appear driven by their strong religious convictions.
Sorry guys/gals my vote is, no speedos in the street, same goes for bikinis and bare chested men in shorts -

this is sounding very unPC

Please cover up when walking the streets - do whatever you like on the beach.
As PJ said - When in Rome