Why women are obliged to remove their nail polish in ablution while they are allowed to wiping over socks?

The analogy you have drawn may sound logical. There seems to be a case for comparison. However, matters of worship are not decided on the basis of logical arguments. In our worship, we follow the Prophet’s guidance. Whatever he says we must follow. That is because he is the messenger who is infallible in matters of faith and worship. On one or two occasions, he suggested certain things, which were not the best course of action in their relevant situations. But these were matters, which have nothing to do with religion. As far as Allah’s message is concerned, he conveyed that to us complete and intact. Everything he said to us is correct. Moreover, it is how Allah wants us to worship Him. With regard to prayer, the Prophet, peace be upon him, instructs us; ‘Pray as you have seen me pray.’ When he went to pilgrimage, he said: ‘Learn from me your rituals.’ Therefore, we do not determine our actions in matters of worship on the basis of logical analogy, but on the basis of what we have learned from the Prophet, peace be upon him. [Added; Islam prohibits prostration or kissing of stones which is termed as idol-worshipping. Yet, during pilgrimage, we are directed to kiss the Black Stone.]

In the case of ablution, when any substance covers any spot of the parts of the body that we need to wash and it prevents water from reaching the skin, then ablution is invalid because it remains incomplete. Therefore, if the nail polish you use prevents water from reaching your nails, it spoils your ablution. Sometimes people use a certain red liquid to heal their cuts or wounds. This takes a long time to wash away, but it does not effect the validity of ablution, [Added: Use of henna, for instance, does not invalidate ablution.] since it does not prevent water from reaching the skin. As for wiping over socks or stockings, we know that the Prophet, peace be upon him, once did that. Hence, it is permissible. But it applies to socks and shoes only, not to any other part of the body. For example, we cannot wipe over gloves or over our sleeves in order not to wash our hands. If we do that, then our ablution is not valid.