In a few situations I find belief in a deity absurd worthy of scorn, but someone that needs to have an omnipotent imaginary friend to make life meaningful and bearable deserves more pity than scorn. To me, such childish fantasy is evidence of a deep fear of uncertainty and the random nature of existence. Religion and deities were created by humans whose understanding of science and nature was almost non-existent in order to explain things they had no way of comprehending. They projected their own image into the role of gods in order to be able to have some sense of control over their lives by asking these beings for their help. The fact that people still believe in these myths is largely due to the same fears and lack of understanding, and having an omnipotent being on your side that tells you everything you want to hear is appealing if not addictive. Add in an education lacking in science and math, critical thinking skills, and how to judge a claim based on its evidence, and it's easy to see how religion still attracts so many. What's easier, learning calculus and biology, or accepting dogma because a deity wants you to use faith?
When someone believes they are doing a god's will, fear and uncertainty largely disappear. Such a belief can also lead to atrocious crimes against others, both physically and psychologically - witch hunts, inquisitions, suicide bombings, genocide, murder and rape have all occurred in the name of piety and religion.
I find it absurd when survivors of a catastrophe believe they were the recipient of divine intervention while others died - thanks is given to a deity, yet no condemnation for killing the victims is expressed. Why were they so special? What made their deity choose them over someone else?
An extremely ill person has a life saving operation or medical treatment. The prayers said for them by others must have worked! Had their friends and family not petitioned the god enough, surely they would have died. The true heroes, the doctors and nurses, are not given as much credit as the magical being watching over them because to do so would be blasphemous.
A friend of mine was kicked out of his home by his mother for not believing in religion. She sent him to his aunt's because she couldn't be around him knowing he would be forever tormented in a lake of fire. Yet she still held onto her notion that god is a benevolent being worthy of praise and devotion regardless of the horrors her child would suffer throughout eternity as taught by her mythology. The same is true for parents that cannot accept the sexual identity their children are born with. Choosing religious doctrine and belief over the well-being and love of your child is detestable.
I don't find these things offensive - I find them absurd and disgusting and indicative of selfishness and ignorance. People can believe whatever they want. It's when those beliefs have negative real world consequences that they deserve condemnation.
As a last thought, I don't want to 'believe' in things. I want to know things. Belief requires faith and unquestioning adherence - knowledge requires evidence and skeptical inquiry.