Reasons for abstaining from Circumcision:

From a medical point of view:

• circumcision has no real medical benefit. None. ( Justified below )
  
• circumcision risks pain, bleeding, infection, and scarring.
  
• recovery can take several weeks to months.
  

From the fake 'health benefits' views:

• Penile Cancer - Already 1 in 100,000 or 0.001% chance of having one, doesn't require cutting.
  
• UTIs - usually occur when urine flows back into the urinary tracts, the foreskin stops some urine from getting outside, but it neither pushes it inside too, chances are 0.1% of having such UTIs, UTIs are more common when men are older and largely due to other different reasons than this one. Not Valid. While on the other hand Meatal Stenosis by circumcision can increase UTIs. ( Meatal Stenonsis 100% found in cut ones, and 0% found in intact ones ) ( you can also retract and pee on regular basis if you want ).
  
• STDs - ( Inner ) Foreskin acts as a place for creating immunological response to STDs, cutting them means you lose the ability to fight back to STDs after you catch one.
  And thats why in African countries, circumcised men have more STDs than intact ones, 450,000 American men died ( upto 2009 data ) due to STDs although they were cut at birth, that USA has both high STDs and high circumcision rate, while Europe and even developing intact countries have lower circumcision rate and low STD rates than USA ( USA has highest STDs in the first world countries )

• The 'Hygenie' - Smegma is actually meant to remove dead cells and impurities from the penis without actually harming it fr. Cut ones don't have this natural mechanism and rely on chaffing ( by clothes ) and other methods for removal, and it takes the toll of keratinizing the glans. Also, cut penises also need to be cleaned time to time, with Americans not cleaning it ( dirtier than uncut ones infact in some cases ) as they assume circumcision is enough. The idea stems from the propaganda of John H. Kellogg and Victorian doctors who labelled Foreskin as a dirty thing since it lead to more masturbation, it was never a dirty thing, it was actually meant to keep the glans safe and clean, To them, it was an immoral perception to them, and the rest of the world ( 75-67% of them ) will laugh at them for this idea.
  

From a scientific point of view:

• humans evolved to have this and it has been evolutionary preserved in most mammals... this is because it serves an important and useful function.
  

From a sexual point of view:

• circumcision decreases sensitivity leading to lower sexual pleasure.
  
• circumcision makes sex more painful for sexual partners and requires more lube.
  
• circumcision increases condom failure rates (breaking and slipping)
  

From a religious point of view:

• it is a cultural practice most common in Jews and Muslims. Christians baptise because of Jesus.
  
• it actually spits in the face of the god or gods that created you... because you are saying that your creation was imperfect, wrong, and needs surgical alteration. It implies people "know better" than god does.
  

From a political point of view:

• circumcision is a pro-capitalist invention where doctors normalise and perform needless procedures to benefit financially... both from the procedure itself as well as from treating the many, many, many complications that can arrise from it.
  
• it was, for a long time, done to make masturbation harder and this was linked to organisations trying to control and limit the sex lives of citizens.
  
• circumcision used to be done on women too... it is now called Female Genital Mutilation (FGM) and is banned in most places. We should also call male circumcision what it is Male Genital Mutilation (MGM) and there are people working very hard to get it banned in men too.
  

From a psychological point of view:

• many circumcised men experience regret, anxiety, depression, and PTSD like symptoms from being cut.
  
• many circumcised men spend years doing foreskin restoration to try and regain their foreskin... because that is the only way they can actually live with their penis without feeling mutilated.
  

From a social point of view:

• there are more people on our planet who are against it rather than for it.
  
• there are more uncut men on our planet than there are cut men.
  
• peer pressure, including pressure from sexual partners, should never determine your actions or your views of your own body. Be an individual. There is only 1 you in the 8 billion humans on our planet.
  

Thanks to u/Fit-Plankton2694 for most of this info ( and fake health benefits part belongs to u/Far_Fly51000 )

Also to note, a Child's foreskin shouldn't be retracted forcefully, as the glans becomes more prone to injuries ( done while circumcising children ) while older children have PTSD issues over 75% of the time ( Phillipines Tuli Data confirms this ).