Yes, I did say is, meaning isn’t.
Those cites show a few tens of thousands of people who were often undocumented- either due to intentionally not registering births, not keeping documents or because they were not adequately informed- who escaped conflicts in the Balkans in the 1990s and crossed borders without being legally documented, from countries that no longer exist. Because of this, some are unable to prove any citizenship, leaving them effectively stateless. Most of these cites are from around 10 years ago, when this first really became widely talked about as an issue; quite a lot of work has been done since to reduce that.
It’s an issue, but the issue is not refusing citizenship until a family has been there enough generations. It’s partly a situation where many Roma see no benefit to engaging in the bureaucracy of the country they live in, especially if they are undocumented or in situations where cultural laws and country laws differ, potentially leaving them at risk of legal trouble, together with some unwillingness of officials to deal with the group. There is ‘othering’ on both sides, it’s not as simple as a ‘them’ being denied citizenship, it’s a group of largely former undocumented refugees who either don’t have the required knowledge or information or -often justifiably- are unwilling to engage with the system. Some may have been resident for 20 years, but if they can’t provide any proof at all of that, it’s going to be difficult. This is especially likely to be the case for those living a nomadic lifestyle with no record of residency or bills.
In all the countries cited, there is a route to citizenship for the people concerned. The issue is not that there is no route to citizenship, it’s not that simple, nor is it a straightforward case of discrimination, and the numbers of people affected now are so much lower than 10 years back, that the anti-statelessness campaign groups have effectively dropped it as an issue.
There are an estimated 6 million Roma living in Europe; while it’s obviously tricky to estimate numbers of undocumented people, I can’t find any reference to it ever being more than 2% of European Roma affected at the very highest estimate.