If you assume that people answered honestly, it's very possible that remaining proportion of people who viewed Asian Americans negatively were more likely to express anti-Asian American racism and hate over the past year, instead of keeping quiet about their views.
Furthermore, a lot of people are biased to skew their responses or lie due to social-desirability bias [1]. The responses are self-reported. It's highly plausible that many people said their opinion "stayed the same" while actually worsening.
Most importantly, anti-Asian hate crimes have "increased by 339 percent" from 2020 to 2021 [2]. Even if you doubt the data, comparatively, crime reports are more reliable and objective than self-reports when you ask a population about their views of people of a particular ethnicity.
[1] https://en.wikipedia.org/wiki/Social-desirability_bias
[2] https://www.nbcnews.com/news/asian-america/anti-asian-hate-c...