Answered by Shaykh Faraz Rabbani
What is the ruling on wearing clothing (designer labels) which has names of disbelievers (and not only that but sometimes sodomites e.g. so-and-so and the like of) whilst praying salat?
It is best not to wear such clothes.
Unless you intend to imitate the kuffar, or do so out of explicit acceptance of the misguided ways of those people, it would not actually be sinful, and would not affect the validity or soundness of the prayer.
[Imitation of the kuffar is only sinful if the imitation was intended, or was in a think that is uniquely characteristic of them, as mentioned by Ibn Abidin in his Hashiya, and by al-Nahlawi in al-Durar al-Mubaha, and others.]
However, one should seek to dress like the believers whenever reasonably possible, and avoid other dress.