In making a judgement on this, one must distinguish between those few cases, for example, religious, which consider it a fact that there is basically no evil, without understanding the necessity of context, and those people who have the same belief but recognise "it all depends".
From the physics point of view it is not difficult to resolve any dilemma here. It is a subject of dualities. The holographic whole has a safety mechanism in allowing its parts to create evil, commit crimes, be selfish, etc. These actions split a perfect energy (sine waves in mathematical holistic balance) into two poles enabling one pole to express evil but the opposite, a mirror image, inherently can cancel it at some time (giving a period of karma).
Thus these poles are interdependent; one can't exist without the other. Evil can't exist without an opposite pole, such as "receivers of evil". In order to erase evil one cannot ever destroy it physically, one must simply stop being a receiver of evil (for example, a victim).
Everything external--all the evil in the world--is apparently a reflection of our internal condition.
If one has studied New-Age material a great deal, a confusion might arise regarding the use of the term mirror-image. It may be used to express both horizontal dualities (both poles in 3D) and vertical dualities (one pole in 3D, the other in 4D or higher). The latter example would be mirror-image projections from the One source, God, of all its forms, that is, the parts, the fragmentations are mirror-images of the source but only in the sense the reflection in a mirror is an (reverse) image of self. This "fragment" doesn't subtract from self--it is a reflected extension and of lower frequency. This is the vertical duality--the lower part (the image) doesn't cancel out the higher source when brought together. With horizontal dualities one pole will cancel out the other for example, gravity/antigravity. The two are complementary--they are equivalent. However, in both cases, vertical and horizontal, a new unity will be formed when brought together.
The question still arises, 'If there is a God, which is infinite, how can it allow all the evil'. One might consider the explanation above as an answer, or the New-Age response, that some living creations of God are given free will. But are these really sastisfactory answers. Can all the suffering that occurs be justified by these reasons? Thus the naive statement about how can there be a God if it allows such suffering, a statement based on little knowledge of the intricacies of the question, really can go quite deep. Maybe the only satisfactory answer is to admit that once the Source has set evolution into operation the fragmented parts, which may go astray, must solve problems at their level of energies/frequencies. After all it is still the one selve (God) extended into these parts, and it can assist from the higher level but is not able to wipe out the problems without considerable work done at the lower level.