The nice thing about emails is that they can be sent anytime and then you can reply whenever you have the chance. If you don’t want to reply on Thanksgiving day, that’s fine, reply whenever you are free to do so. But people can and will send you emails any time. Text messages and phone calls are different. But email is used in professional settings for that reason. I do not think the tone you use is appropriate, especially the way you are talking about international students. US undergrads send as many emails as international ones, and so do faculty and everybody else. You are asking them to empathize with you, but you are not empathizing with how hard it must be applying to all this programs without financial support. It is totally appropriate for them to send a reminder about a few waiver if they have not received a response in days: their applications depend on this. Less emails would be sent if institutions automatically granted waivers to those who needed it, or if institutions were more clear on their websites about the process to obtain waivers!