This is true.
Inflation-linked benefits and tax credits will rise by 10.1% from April 2023, in line with the Consumer Prices Index (CPI) rate of inflation in September 2022. Similarly, pensions are currently subject to the "triple lock", meaning that they are guaranteed to rise in line with the higher of CPI (as at September 2022), average earnings between May 2022 and July 2022, or 2.5 per cent. So these will raise by 10.1% in April too. Students are seeing the maximum maintenance loan increasing by just 2.8%.
So why shouldn't student loans increase by 10.1% too? I don't know what argument the Government would put forward here, but I
suspect it's simply that they have less of a "voice" then those claiming benefits and pensioners:
(a) There are 2.66 million students at UK higher education institutions (mostly studying first degrees; figures from 2021/21 figures) (
source). As of February 2022, 22 million people were claiming some form of benefits*, in England, Scotland and Wales (
source). As of February 2022, the number of people receiving State Pension was 12.5 million. (
source)
(b) Across the last three general elections, of those in the 18-24 age group (which most students will be), only about 50% voted; for those in the 65-74 and 75+ age groups (which most pensioners will be), in excess of 80% voted. Of the other age groups average about 70% voted (
source).
So, the group who received a 10.1% increase is comprised of 32.5 million people, 70-80% of whom vote. The group who received a 2.8% increase is comprised of 2.66 million students, about 50% of whom vote. (Correlation is not the same as causation.)
* I realise that not all 22 million benefit claimants will see their benefits increase by 10.1%, as only those benefits which are inflation-linked are increasing by that amount. However, I couldn't be bothered to work out which are inflation-linked and which aren't, and then lookup-the stats per benefit, avoiding counting the same claimants twice.