This is just political excuses for the rule.
First, if you're going to let a team "join" the league, then you have to let that team join on a full and equal basis. To have a different set of rules for one or more teams within the league is discriminatory in itslef, and results in inequality. Sport is all about a level playing pitch for all participants. MLS are not giving us that (whether it goes for or against us, the point is it's unequal).
Second, what did MLSE pay the money for if they get shafted on the unequal application of the rules?
Third, why should we be charged to see a team that is playng against a handicap? Where's the discount on ticket prices that the league picks up for that? (And beers
)
Fourth, none of this is even necessary, you can keep the domestic and non domestic split and just change the rules on how many of each must or must not be contained within a roster. MLS is always changing this anyway so clearly there's not a concrete rule set down by the government. They could just as easily reduce or increase the numbers to a point where we;re basically not handicapped anymore, without even being affected by the immigration issue.
There may be a genuine reason why this has to be in place, btu I have yet to see or hear about one.