I'm slightly confused with certain gameplay stuff I recently found out...

It seems that a Fusion summon cannot be negated, unless you negate the activation of the fusing card itself.

The effects of "Thunder King Rai-Oh", "Black Horn of Heaven", "Solemn Judgment", and similar cards cannot negate a Special Summon by another card effect.[6]
Example: Cards like "Thunder King Rai-Oh" cannot negate the Special Summon by the effects of "Monster Reborn" or "Polymerization". However, "Solemn Judgment" can also negate the activation of a Spell/Trap Card, so it can negate the activation of "Monster Reborn" or "Polymerization" itself.[6]

http://yugioh.wikia.com/wiki/Card_Rulings:Solemn_Judgment

People negate my fusion summons all the time -,-
does this mean you just can't negate the summon or is the fusion summon not a Chainable event at all? (Ex-Bottomless Trap Hole, Torrential Tribute, etc)

torrential and stuff like that works because they don't negate. it's just in response to the summon of a monster. and no thuner king / solemn judgment can't negate the actual summoning of the monster because it's still the resolution of the spell card. and their effects say "negate the special summon of a monster" not the effect that special summons a monster.

Super poly=truly unnegatable card x3