First, it speaks of the populist nature that is inherent in traditionalism. According to Fr. Rosica, liturgical rubrics really just matter to experts instead of the faithful. This kind of thinking is what led to the wasteland of the Post Vatican II era. It essentially tells the Catholic faithful to keep their mouths shut, don't care about what is in the liturgy, just pray, pay, and obey. This kind of age led to rampant liturgical abuse, and tracked in almost linear fashion with the decline of faith following the Council. Blessed John Paul II admitted near the end of his pontificate that he allowed this attitude to fester way too much, and that it damaged far more than just the state of the liturgy. It is for this reason that the work Redemptionis Sacramentum states the following:
On the contrary, it is the right of all of Christ’s faithful that the Liturgy, and in particular the celebration of Holy Mass, should truly be as the Church wishes, according to her stipulations as prescribed in the liturgical books and in the other laws and norms. Likewise, the Catholic people have the right that the Sacrifice of the Holy Mass should be celebrated for them in an integral manner, according to the entire doctrine of the Church’s Magisterium. Finally, it is the Catholic community’s right that the celebration of the Most Holy Eucharist should be carried out for it in such a manner that it truly stands out as a sacrament of unity, to the exclusion of all blemishes and actions that might engender divisions and factions in the Church.In the end, it doesn't really matter whether or not someone is a liturgical scholar or expert. They still have an expectation of a liturgy according to the norms.
Dr. Edward Peters also touches on another problem with the statement: it presents a separation between law and spirit which, quite frankly, isn't Catholic. Quite the contrary, any authentic Catholic reform comes from a healthy obedience to laws and regulations concerning Catholic practice. Religious orders were only restored via a return (in many cases a radical one) return to their rules and constitutions surrounding their following. The beauty of the reform of the Counter-Reformation was how the Church shed those practices which led to the flouting of Church laws. Once those laws were followed with greater frequency, general holiness flourished, the Church won converts, and some of the highest level of thought occurred. Christ did not come to abolish the law, but to fulfill it. Most of the calls for reform since the Council have followed the outline Fr. Rosica advocates, and the results have been by all accounts disastrous. The reforms of the past two pontificates (more or less) rejected this mindset and the results have been far better. (Look at the young generation of priests and the overall beliefs of catholics who attend Mass regularly to see that their approach has succeeded.) Not ideal (such an ideal is not possible this side of the eschaton), but positive.
These concerns aren't just the concerns of traditionalists, and I would argue that is what makes our way of doings things so appealing to many in light of this controversy.