This is the disgusting consequence of giving government too much power and is a perfect example of the corrupting consequence to allowing governments to meddle in the private affairs of businesses like this. The individuals involved invariably bring their own biases (we all have them, the problem is when we think it's OK to force them on others, and that's what governments tend to do -- what else can you do with all that power?) and end up choosing sides between competing companies, instead of letting them fight it out for the good of customers.
The very notion that it's "abusive" is absurd. Unless it's based on limited access to specific natural resources (never the case with these tech issues), a monopoly that's bad for customers can't stand in the long term without support from the government (e.g., prohibiting or regulating business practices to require features owned by the market leader -- a common consequence of heavy lobbying by the big companies that can afford it, which is why regulations ALWAYS help the big companies and hurt the small scrappy newcomers). There's no point in spending big bucks to lobby a small government. Big government drives the lobbying industry, as all that power attracts people attempting to influence it for their benefit. So, if you want to reduce money in politics, first you limit what government is allowed to do to its people and businesses, then Slack and MS don't spend as much as small country GDPs to influence the various governments where they conduct business. They'll only spend that where they believe there's a receptive audience with the power to help them.
Otherwise, upstart competitors always find clever ways to solve the problems the market leader is causing (whether it's high prices, lack of features, whatever). Beating competitors is not a problem for consumers. It's a problem for the competitors and they need to fight harder to win customers. That's the ONLY way to ensure that customers win.
If competitors can instead turn to the government for assistance, that merely ensures they don't work as hard to woo and delight customers, which is BAD for customers in the long run.
This is the legacy of this EU state of affairs, short-term apparent wins (yay, Apple will now use USB-C) that yield a long-term reduction in innovation and worse conditions for consumers.