Never really could figure out this whole "stumbling" thing.
On the one hand, anyone who causes another to "stumble" is better off dead, per Jesus' words about the millstone.
On the other hand, Psalm 119:165 says "Abundant peace belongs to those loving your law, and for them there is no stumbling block".
So, if someone stumbles...
Does that mean he is "unrighteous"? Whose fault is it? The guy who caused the stumble, or the stumbler who, by virtue of "stumbling", is not "righteous" per Psalm 119:165? If he were "righteous" he wouldn't have "stumbled", right?
If you go around avoiding doing things because you might "stumble" someone, pretty soon you'll just be living in a hermetically sealed bubble with no contact with anyone. Some idiots are offended by what color socks you wear (we've got one in our KH).