Photoshop (and other similar programs like GIMP or Paint .net) are really useful. Not all logos you need are in png format without background. Of course, you will find a lot of the most famous logos already in that quality, but if you want a custom logo or a logo from a smaller team you won't find it that easily.
Removing backgrounds is not always hard, paint. net (and others) have a magic wand tool that helps with that.
Also, if you are a perfeccionist, please note that Wikipedia many times don't have the official version of the logos. You'll often find logos in there with slightly different colors or fonts, most likely because they were not directly taken from official sources. If that doesn't bother you, sure, go ahead, but I prefer to take the logos from the official club websites or social media.