you wouldn't consider the Saltire to be racist but the union flag would be?
I don't really think much of anything when it comes to flags, because I perceive notions like patriotism to be a bit silly. Nobody has control over where they are born, it's simple accident of birth, and I find that wherever I've gone in the world I meet some people who are of a similar outlook to me, and others that couldn't be more different, so I don't even subscribe to any theories about Scots, or Brits, having any particular commonality beyond occupying bits of land that share borders.
I see flags as representations of tribalism and the sort of world that most people are glad to have moved on from, if anything, and don't feel any affinity with any of them. It's just another expression of daft notions like patriotism. There's nothing to be "proud" about having been born somewhere. Nothing to be ashamed of either, but I just don't see sharing a birth place as somehow a common unifying factor between people when two people can live next door to each other and be complete opposites in every respect, yet have everything in common with someone on the other side of the planet who they have never met.
I suppose if anything, I'm always a bit wary of anyone who expresses any strong association with any flag, and it's why I don't really go in for bunting and overt displays of national belonging, even though I accept for most people it signifies nothing more than their own, personal, sense of belonging. It's not for me though.
I think any flag can be used as a tool of racists, hence why I will always point out that Scottish "nationalists" are not one homogenous mass, because there is a small number of people who associate themselves with the movement who are, for all intents and purposes, "blood and soil" type Nationalists. They still wave around the Saltire, but I don't view it as synonymous with them or their brand of Nationalism, and nor do I view it as sullied by association. It's why I, personally, will not wave around a Saltire though, because I don't want to be taken for that sort of extremist or someone with exclusionary views. To that extent, I can understand why English people might be wary of carrying their own flag around, or that of the Union.
I am a republican, and since the Union flag is invariably linked with the monarchy, I find it objectionable in that respect, but I don't automatically link it with racism. To me it's more synonymous with Sectarianism, because it's often co-opted by Scots who are themselves sectarian bigots, and revel in overt displays of their own bigotry, so if you really pushed me I'd probably admit that I view it as a symbol of bigotry more than straightforward racism. I think if there are negative perceptions of the Union flag they will vary depending on location though, and that one is particular to Scotland and possibly NI. I can't speak for how people in Northern Ireland view it though.