The mindset of the person giving the shoes isn't an issue one way or the other.
Simple facts though will suggest that the people who can afford Nikes are also savvy enough to know the advantages of donating them (write offs) over simply throwing those K-Mart specials away.
This simple fact which most people don't think about, is that most of the shelters carry a LOT of used top shelf items. Such as Nike.
Being perplexed because a homeless guy turns down a pair of sneakers with what seems to be a snooty "only if they're Nike" attitude, shouldn't be seen as anything but an odd mindset of the homeless. ( if they weren't a little odd, they probably wouldn't be homeless.)
If you have a pair of shoes for the needy, the best bet is to donate them to a shelter.
A homeless man who is barefoot is probably barefoot by choice. If indeed, he felt he was in need of shoes, a quick stop at the shelter will get him a good pair of Nikes.
If indeed, you want to be involved in helping the homeless, there's many ways of doing it. A few obvious ones are volunteering at soup kitchens, food pantries, even the shelters will take on volunteers to sort, launder, fold, and distribute the clothing.
A woman here in town who died recently would spend all summer collecting blankets, gloves, socks, watch caps, scarves.
Any cold weather items.
When cold weather set in, she and her husband would visit the homeless camps in the evening. With a huge pot of coffee and hot soup, they would sit by the fires and talk to the homeless, find out what they needed and make sure that each of them were going to make it through the night.
There's only two things a homeless man will NEVER turn down. Folding money and pocket change.
The two things you should NEVER offer to the homeless.
If you simply want to feel warm and fuzzy about yourself, give the homeless guy a buck.
He'll most likely take that buck and buy himself a liquid refreshment so, he too, can feel warm and fuzzy.
Want to help? Sit down with them over a cup of coffee.