AITA for being upset about SIL showing up to a wedding empty handed

I got married a few weeks ago and after going through all the gifts I realized my husband's sister didn't get us a single thing for our wedding. I understand that her and her husband aren't doing well financially. They have 4 kids. One each from a different marriage and twins together and they are living well below the poverty line so I did put very affordable stuff on there. I find it hard to believe they couldn't at the very least get $20 LED light salt and pepper dispensers. They got nothing. I texted her saying I couldn't find their gift and she said she told my husband they couldn't afford a gift and he said it's fine and to just be there for him is fine. I asked why she didn't think to ask the bride. I'm not trying to sound like a bridezilla but in reality we are the ones who take care of most of the wedding planning. It is my husband's day too but if we are being realistic historically it's always been about the bride. My husband just had to buy a tux and show up. I did a lot of the wedding planning. Got my hair and makeup done and this was an important day to me. I'm not okay with the fact that I fed a family of 6 who didn't bother to get me anything. Especially since it's normal wedding etiquette to at least spend $500 on the couple.

Edit: Wow. So much for an app where women can support women. I understand their financial situation. But if they're okay with gobbling down food they didn't pay for they should get something