No matter how reprehensible something may be, banning anything legal will always infringe on free speech.
These measures, including those UEA and the SU have advocated impose particular viewpoints and moral standards over everyone regardless of whether they can even be justified.
The vague language used by UEA inhibits students’ free speech. For example, leaflets “likely to cause offence” are not allowed. The criteria means that a wide-ranging list of topics or wording could be construed as offensive and so means that the rules are more likely to be enforced arbitrarily.
While such policies are well-intended, they target the symptom, not the problem. Banning offensive speech does not eradicate offensive thoughts. It just makes it harder to find people who hold disagreeable viewpoints. Instead of being able to avoid someone who, for example, supports Trump’s policies, you are left in the dark. People hold their tongue and reveal their colours at the voting booth.
The banning of newspapers and sombreros at UEA is slacktivism at its finest, actions which are motivated by a perceived need to reduce offence (even in cases where no offence was caused). As for claims that these restrictions help protect people, perotections already exist. They’re called laws.