The two positions that are being argued are that:
a) The bastard sword (and dwarven waraxe, etc.) is an exotic weapon, and there is therefore no such thing as MWP: bastard sword. This has the consequences that the only characters who can use these weapons two-handed without a -4 NWP are characters that have the EWP, or characters with the class feature 'proficient with all martial weapons'.
vs.
b) the bastard sword is an exotic one-handed weapon, or a martial two-handed weapon, and can be treated either way as necessary. So, a character could take MWP: bastard sword, and would be able to use one two-handed without penalty; a cleric of Mayaheine with the War domain can use a one two-handed, etc.
The 'bard with fifty MWP feats' is just a rhetorical device, an attempt to demonstrate the absurdity of position a). I don't think anyone would seriously suggest that such a character would really be entitled to use a bastard sword two-handed as a martial weapon; rather, the suggestion is that the MWP: bastard sword should be one of the feat options available to him. Otherwise, the only difference in melee proficiencies between this character and a fighter with no EWPs, except that the fighter can use the bastard sword two-handed and the bard cannot ... And if the bard takes the EWP, then he can use the bastard sword one-handed and the fighter cannot. There's no feat combination possible that the bard could take that would match the fighter's proficiency--the bard either falls short or exceeds the fighter's weapon abilities.
Personally, I really don't see what the point is about arguing over the RAW in this kind of case. Frankly, any DM who refuses to allow a character to take MWP: bastard sword & forces him to take the (superior) EWP: bastard sword feat because 'by the RAW, the bastard sword is an exotic weapon', is just being a hand-and-a-half. If you know what I mean.