Engineers Without Borders USA interview questions

The interview process felt well organized. After submitting my application, I received a set of screener questions, including questions on salary expectations, motivation for applying, and views on non-profit communications. The organization responded quickly asking for a phone interview, which took place with the hiring manager and two members of the communications team. A few days later, I was invited for an in-person interview that involved additional members of the leadership team. The following day, I received a phone call from the hiring manager expressing their interest in having me join the team. I was told it was a rare situation where every person involved in the interview process thought I was a great fit for the team and the role. I agreed, and asked for a formal offer letter. Later that day, a member of the communications team emailed me to say that she was excited for me to join the team (a super nice touch!). The salary offered was within my requested salary range, and I was prepared to formally accept it. However, after reviewing the full benefits package, I learned that my insurance premiums would raise significantly under their plan. I called the hiring manager and asked her about the health insurance policy and was informed that there was no flexibility on the employee's portion of the premiums. With this in mind, I emailed a counteroffer that took into consideration the higher healthcare premiums. The hiring manager then emailed to say that he/she had forgotten a $9,000 healthcare stipend offered to employees to help offset these high premiums. Okay! I was confused why that wasn't communicated when the question was asked, but was happy to hear that the higher premiums would be more manageable. I sent a follow-up email with a second counteroffer, asking for a 5.5% increase in the base salary, and informing them I was ready to accept the offer that day. I heard nothing in response for 7 days, so I followed up again and was told that the hiring manager was on vacation. I thought the lack of communication was strange, but was still generally interested in the role and was convinced that all indications suggested they were still keen on my candidacy. When the hiring manager returned from vacation, we scheduled a phone call. I was informed that the organization was now looking at other candidates because I "negotiated so hard" and was possibly unfamiliar with non-profit salary expectations. I found this information surprising given I had requested a modest increase in the base salary and have, in fact, worked exclusively in the non-profit industry for more than a decade. Regardless, I was still interested in the role, so emailed a new counteroffer. Again, I didn't receive a response. No email. No phone call. Just radio silence. Ultimately, I emailed to say that the lack of communication concerned me and I was withdrawing my candidacy for the role. I'm uncertain if the lack of communication was the result of the other candidate they pursued or reflective of more general organizational culture.