I learned about this initiative from professors Roberto Battison and Silvano Tagliagambe, following the climate of increasing repression against freedom of research and speech in universities in the USA. A new era of authoritarianism has begun with the election of the new President of the United States. In a democratic country, forces should be balanced. Therefore, a slight friction between different bodies is always expected. However, here the institutions are not well balanced, and one is striking hard, which is exceptional. Most American universities are reacting, and – hopefully – the previous status quo will be regained. However, individual researchers, especially those in precarious positions, are more vulnerable. They will think twice before moving to the US or continuing their careers there. Those whose views are not aligned with the current US administration will face the greatest risks.
Allowing these individuals to continue their careers in Europe is not only a tactical move for the EU, but also a way to support European values such as diversity, democracy, and tolerance. When the US, in a few years, sees how their policies have ruined their research outcomes, business, and academic relationships with other countries, they will recognize how democratic values are beneficial for the well-being of the people and the development of knowledge.
The document (Italian only) can be signed here
In the meanwhile, watch how things unroll in the US. The number of EU citizens moving to the US has dropped dramatically (Figure 1) and the public spending in the US has increased compared to last two years, notwithstanding the DOGE propaganda about cutting public costs (Figure 2). Note that data comes from US departments.

Figure 1 (source: Financial Times https://www.ft.com/content/6dc16a54-8de1-4f3b-8409-ecb566118127)

Figure 2 (source: Wall Street Journal https://www.wsj.com/politics/policy/trump-doge-government-spending-increases-5903992d?lctg=84541483)