I wont so much answer your questions as to give you my thoughts.
Well i will anwser your questions and give you miy thoughts.
1/ Porno is for pure self gratification. J'ing Off.
2/Yes they do....Not saying that woman dont watch porno..or that some women who do porno dont enjoy it..but just because they enjoy it dosnt mean it is good for them either.
You will find the key element missing from all Porn is....ROMANCE. THere is No roamnce nor is there any love...just pure Animilistic instinct for Self graticication...how often do you see porn with Kissing?
3/ yes and no...the objectivity of women has around before Prono became more mainstream..not the other way around.
but define the object... Ie: Women are for children and cleaning and looking after there husband.
That is the reason women went into porno mostly...to free them selves from that ideology.... Ive got more to add on this but i would be going on.
4/ Yes, and they are very easy to access on the net.
5/Yes they are....Some maybe able to watch them and have no effects. but they really dont need to watch them in the first place. "Remeber everything is Permissable..but not Beneficial for you"
That said...Porno does effect weaker willed people..it is lie a Snowball heading down a hil and gathering size as it rolls.
You may watch your first Porno and get off to it...but next time that porno dont cut it....you want to see something new...prehaps the man being more dominant. or just to see a diffrent naked woman in a new location.
This gos on and on...until you find your self looking at the filthiest porno or trying to act out the scenes in the real world.
The best example of a weak willed individual who took porno too far was Ted Bundy.
This link will show you Ted Bundys last Interview before being executed.
http://www.pureintimacy.org/gr/intimacy/understanding/a0000082.cfm
Now that dosnt mean everyone is going to Turn in to a Pyscho...but there are milder forms. even relating to women is made more difficult by watching porn.
Remeber also that if your a Aetheist, Agnostic or Evoloution beleiever....they dont really see porn any diffrent that some pure scitific level where it is just your sex drive...and it is OK...but when you beleive in a god..you will most likely find that they frown upon Porn ..even though some may be weak and still watch it.