Yes, the Estonian government could probably make it easier for Russians who are fluent in the language (a strong indicator of willingness to be part of the country) to become citizens. But mostly this sounds like Russian feelings of superiority and cultural and linguistic inertia. They’ve been living in Estonia for 25 years. There is no excuse for every Russian there to not be brilliantly fluent in Estonian. Estonians were not given a choice about living in the USSR and learning Russian for 50 years (and they did a better job at the language than the current feckless Russian speaking population).
“Too hard” and “I can’t practice” and “They speak my language” are not valid reasons for failing to learn a national language. They are all excuses made after the decision has been made to not learn a language “They’re not friendly” and “They made fun of me” are also post facto rationalizations and not real reasons that people don’t learn a language they need.
The real concern is that rather than cross a border they want the border to cross them. Putin is clearly itching to show NATO up and clearly NATO will not risk war over a sliver of a tiny country.
But these people are not victims of discrimination they’re victims of their own choices.