Simple Q&A D&D 3.5 (by RAW) XXII

[Andezzar]

Shield Proficiency only applies to bucklers, light and heavy shields.

Please quote that in the rules.

Look at the Bastard Sword, it's a sword, just like a long sword and a greatsword...except you need exotic weapon proficiency Bastard Sword to use it instead of Martial Weapon proficiency.

Read the rules again. The bastard sword only requires EWP: Bastard Sword if you want to use it one-handed (and then also requires STR 13). Otherwise it's a martial weapon.

Weapons are clear, there are three obviously distinct proficiencies: simple weapon proficiency, martial weapon proficiency and exotic weapon proficiency, and there is no feat/class feature called weapon proficiency.

Shields however do not have a simple/regular shield proficiency. There is Shield proficiency, Tower Shield proficiency and Exotic Shield Proficiency. Those are not obviously distinct, as evidenced by the explicit exclusion of tower shields. A tower shield is a shield, and unless stated in the individual item's description, so are exotic shields.

Anything exotic is definitely excluded, otherwise it wouldn't be exotic.

That is just an assumption, not a rule.