Loose constructionists say that courts should practice judicial activism by abiding by what the Constitution figuratively says. The converse of this is the idea that the United States Constitution should be interpreted strictly, refusing to creating new rights that aren't explicitly in the Constitution. The Constitution itself spells out the procedures for amending the document to include new rights. Loose constructionists disrespect this process, unlike strict constructionists.
Loose constructionism was originally advocated by Hamilton in order to allow the American School to be executed, which was very nationalist. Cases that used loose constructionism were not usually forms of judicial activism, as Hamilton condemned it in Federalist Paper No. 78. However, liberals started to use it over time to justify wrongly-reasoned court decisions that allowed many of their economic programs to exist that were meant to promote "equality". Therefore, it became a tool used by liberals to undermine the legitimacy of the judicial branch.