The only metric that page uses to define India as socialist is “makes a constitutional reference to socialism”. That can mean socialism is some end goal, or they just have policy inspired by socialism.
Words have definitions, so just saying “this country is socialist” is not enough evidence to declare that country is socialist, unless your definition of socialism is “a system which people call socialist”.
By that definition, America is socialist so long as I call it socialist. It becomes tautological and useless.